Adjusted for inflation, a 1985 Toyota Tercel would cost a lot more than $10,000 today. When my parents bought a new Nissan Sentra in 1983, they paid $5,000. That's $17,000 in 2026 dollars for a two-door car with a 5-speed manual transmission, hand-crank windows, manual locks, and no radio. Safety equipment consisted of seat belts and that's it. The car was built like a tin can. Making a car like that meet modern safety standards would add even more to the cost. Believe it or not, the manual features would probably add to the cost because now there are tooling costs to build parts that aren't in common use anymore and need mechanical linkages. Power windows can just use a motorized lead screw to move the window and then just use wires to connect that motor to the control switches. Mechanical windows need a physical linkage from the crank all the way to the window regulator, making for a rather large assembly that has to be designed with a specific door in mind.

The only way I see a <$10,000 car being possible is to make that car using virtual slave labor in the poorest countries capable of building vehicles, and even then it will probably be cautionary tale about getting what you pay for.