US employers assume adults can drive. Presumably, if they're hiring you as a delivery driver, they will confirm the appropriate licensing. But, if you're a random engineer that they discover can't go to various customer sites without all sorts of special arrangements, a lot of companies are probably going to take that into consideration come review time.

Fair enough, I guess in the US one should make that clear during the hiring interview.

I wonder what US employers will do when the next generations of employees come in and their assumption starts failing hard.

Seems pretty straightforward. If it becomes an actual problem, they start calling it out and make it a requirement, even if it's negotiable.

ADDED: The reality is that there are lots of implicit assumptions in a professional job. Unless it's a job that involves significant/regular travel, they probably won't ask you if you're willing to step on a plane. They probably won't ask you if you're OK with attending meetings before 10am. Etc. If you have out-of-mainstream requirements it's probably mostly on you to raise them.

In the US it's sort of implicit for most professional or technical positions that you'll have to take occasional business trips, and some places you go may not have much public transit or taxis / ride hailing services. A lot of hiring managers just assume everyone has a driver's license and can rent a car if necessary.