Part 2:

and the financial math won’t change either.

Correct. When the just express tollway network on I635 has had more investment than the entire light rail network and individual highway upgrade projects cost in similar price ranges to entire rail lines (I345 upgrade is expected to be 1.6 billion, the Silver Line cost 2.1 billion and thats with Covid hitting right as the project got started leading major delays and a cost blowout), the math for car dependency will continue to be terrible for municipalities. Highways are hideously expensive, and Dallas has the unique burden of having all of its road infrastructure beat up by the vehicles of all the suburbanites who dont actually pay significant tax revenue to the city to cover the damages. Lets also not ignore the millions in economic damage due to accidents (or the lives lost and ruined), the billions needed in repairs for legacy infrastructure, nor the fact that sprawl increases costs for providing and maintaining utilities and services since, as mentioned before, they all scale in cost significantly more with area than with population. The individual math for personal car ownership has also continued to get worse (again, average 30k for USED vehicles, with anything in even half decent condition being over 15k even for the economy sedans), with continual price increases (tariffs have already brought prices back to covid highs in the used and new car markets), insurance getting ever more expensive, etc. A yearly DART pass was about $1200. Some people get "free" corporate passes, reduced rate student passes, etc. In general the max you'll ever pay for DART on a yearly basis is about $1500 even after the price increases. Thats less than just my insurance payments on a shared vehicle (btw its a used vehicle from 2016 so not exactly a high price luxury car). Including gas, maintenance, and the actual payments makes DART is significantly cheaper on a personal basis for the majority of individuals, its just going to be slower or not an option given its current scale and the existing built out environment.

But that gets to the point of all of this: the existing built environment can change. The sprawl is so extreme that youre right, that we won't be able to change the entire metro even over the course of 30 years. However, we can encourage development and density around DARTs existing network (which until like 2 years ago was the most extensive light rail network in the US). We can densify and enable car free or car lite lifestyles around areas where thats already somewhat the case (like Uptown, and if including the suburbs then Citiline, DT Plano, DT Carrollton, Las Colinas, Addison, etc).

Its taking these areas that already have promise and removing existing restrictions on their growth such as parking minimums, density maximums, and a whole host of minor regulations that add up to make building dense transit oriented developments considerably more expensive than they should be. Its not a case of doing everything at once. Theres islands of density and walkability, and theres an existing substantial transit system (albeit nowhere near large enough for a metro area of this size).

So the first steps would actually see the biggest and easiest improvements in this regard: bring transit to the areas that can properly utilize it but dont have it (easy examples are the Legacy area in Plano and North Arlington) and build dense places that can properly utilize existing transit infrastructure (easy examples are basically all of the light rail park 'n rides except for like Parker Road). Both of those efforts are very doable in 20 years (hell they're probably doable in 10) and would absolutely create massive increases in transit utilization and ridership while being a financial boon to the city and individuals/families who can cut out at least one major expense and possibly more when they live in the areas that make it possible.

Replying in 2 parts since reddit cant handle the full response in a single reply. Part 1:

I get where you’re coming from, but I don’t buy that “just add density” fixes the car-dependency problem.

It has worked in select neighborhoods so far, but the city needs to hit a critical mass for it to begin happening to any significant degree. Areas like Uptown are great, but Uptown is an island in a sea of sprawl. However, the city and DART have switched focus to building out dense mixed use development around DARTs' existing stations. While this won't completely remove car dependency (especially meteo wide) itll create more and more pockets where people can live car free or at least car lite (such as sharing 1 car for a family rather than 1 car per adult). Theres already areas like this that are growing, but it's definitely going to take decades before any significant shifts happen metro wide.

Developers capture profit up front, but the city is stuck with the long-term bill for roads, sewers, utilities, and services. That supposed “density dividend” rarely balances out in Sun Belt metros — you often just get more cars per acre, not fewer.

You've missed a very critical point with this statement: every single one of those utilities (except parking) increases significantly more with area than with population. So building denser generally is less expensive for the city to maintain due to the relatively larger tax base per acre, which also matters for many other services like police and EMS which scale in cost with service area as well. The city also doesnt usually maintain things like public parking garages or parking lots to anywhere near the same degree as roads and utilities, so the increased cost for those due to density is borne more by the developers/owners rather than the city.

And the cultural reality matters. In Dallas, 90%+ of commuters drive. People here overwhelmingly value cars, space, and flexibility.

You act like it's always been this way. In 1946 somewhere between 25%-50% of people in Dallas used public transit (while the total population was significantly smaller, the raw number of public transit trips was almost double what it is today). This is after almost 3 decades of declining public transit ridership within the city. 90% of people also drive because they don't have any other choice. Wanting to drive and being forced to drive are not the same thing. For anyone living outside of loop 12 its essentially not a choice unless they live in one of the few neighborhoods that has a rail station or decent bus stop.

And while yes, people value their space and flexibility, they also value their lives. Driving around here is extremely dangerous, and despite all the shit DART gets about being dangerous and sketchy, even if every single murder in the entire city of Dallas occured on a DART vehicle or station then itd be roughly as dangerous as driving, at least in raw numbers. However theres maybe 3 people per year killed on DART property (most of which occur in neighborhoods that are already dangerous with or without DART) and over 200 people per year killed in car crashes just within Dallas city limits. You could probably throw in another hundred fatalities across the other DART member cities. That's to say nothing of the thousands of people critically injured and tens of thousands of minor dings that still result in significant financial strain, nor to mention things like car break-ins or car theft. DARTs reputation as dangerous comes much more from the fact that the danger feels more personal, not from the fact that youre more likely to die or get mugged on it than be in a car crash (minor or severe).

There's also the fact that Gen-Z and younger generations are showing signs of really not liking cars. Who knew that having a 30k fee to participate in society would make the youth not want that anymore? Btw 30k is now the nationwide average sale price for USED cars. Average new is over 50k. Culturally you (well, people with your position) are in for a hell of a rude awakening when Gen Z and younger come to full prominence since we arent particularly fond of the crippling debt required to participate in a car dependent society. The cultural landscape of specifically Gen Z and younger is very different from Millenials and older in this regard, and its going to become more and more of a factor 20 years from now as boomers die out, Gen X fully hits retirement, and the kids of millenials begin to become adults.

You can’t legislate that away with zoning tweaks.

The current dichotomy only exists due to over restrictive regulations. It's not a coincidence that when Dallas started allowing density in certain neighborhoods (like Uptown), it started getting built extremely quickly. For the past 60 ish years its been illegal to build density and transit oriented developments throughout 95% of the city. It's also very noteworthy that Dallas bulldozed a lot of neighborhoods to make way for the freeways and parking lots, which enable car dependency within the city.

Until transit actually competes with a 30-minute car trip, most residents simply aren’t going to switch

In certain cases, it does, especially the light rail network during rush hour. The biggest issue with it is that not enough people live within a convenient distance of a rail station (which is why densifying around them is such a good idea). Many people are also willing to accept slightly longer trips for the convenience of not driving. Its stressful and Dallas drivers are fucking maniacs at the best of times. Its worth a slightly longer trip to reduce the stress on a daily commute. With how sprawling DFW is its going to be impossible to make transit the best option for every trip for every person within this century (and thats being optimistic), but its absolutely possible to make it the best option for certain trips (namely in/around downtown and adjacent neighborhoods, the airport, and the downtowns/urban neighborhoods of several major suburbs).