Those that can’t afford increasingly costly cars will have to live in 15-minute cities, where everything is supposedly within walking distance. From Eric Peters at ericpetersautos.com:

It is no longer possible to find a new car for less than $20,000. Soon it will probably be difficult to find one under $30,000 – thanks to the 25 percent tax that will be folded into the cost of just about every car (and crossover) with a price around $25,000.
Not to mention most trucks, too.
Because almost all of those are not made in the United States, either – and they will all be hit with the 25 percent tax Trump likes to call a “tariff,” so as to try to get people to not think they’re paying it.
And how much will they be paying for this tax? Bloomberg estimates the per car cost – for cars not made in the United States – will be in the vicinity of $5,855. This would raise the base price of a car such as the 2025 Kia K4 (which I recently test drove and wrote about here, if interested) from $21,990 to $27,845 – putting this for-the-moment affordable Korean-made car into the unaffordable range. It is one of many – the Hyundai Elantra is another – that will be so rendered via the tax the president insists on calling a “tariff” – for the same essential reason that the government insists on calling the 15 percent lopped off every dollar we earn a “contribution” to Social(ist) (in)Security.
“It’s going to be a real struggle for buyers,” said Erin Keating, executive analyst at Cox Automotive. “We only expect prices to rise and incentives will go away. Some vehicles could go away.”

This is why I am willing to put $5,855 into body work to keep my 24 year old Nissan Maxima SE (and myself), running free.
22-year-old Ford Taurus here. An added bonus: my brother was a Ford mechanic and then he taught auto mechanics. He’s got former students who will work on my car at reduced rates and not charge a markup on parts.
And cash under the table is frequently an option:)
tomorrow’s ghettos