From the data we have so far, EV batteries only seem to lose about 1% per year, with a 15 year Model S typically around 85%. We don't have the data on how that does over even more time, but that is also battery tech from 15 years ago. Even so, batteries can theoretically be replaced just like an engine, and the savings in maintenance, fluid changes, and cheaper energy over the life of the vehicle makes even a $10k swap job worth it if you really want to keep the vehicle.

Range is the biggest concern, but even fully loaded with poor aero, big tires, and an old battery, you can probably wring 240 miles of on-road range in a bad scenario. I bet a fair number of tacomas and jeeps probably don't even get that, and the only limit is a charger which requires some planning, but its not that different from gas. Just a little more restrictive, but less so every year.

Worst case scenario, even the tiny little portable generators are capable of 2000 watts, and so theoretically you can probably get around 5-6 miles added per hour. Really inefficient use of gas, but it can extend your range a fair amount if you really need it.