I don't foresee cars ever becoming unnecessary, since that's the only feasible way to get to work without being severely limited in your choice of employers, and having little or no choice of employer would be feudalism in all but name.

That said, work isn't the only place you need to go. Neighborhoods ought to include shops, restaurants, and the like, too. Here in suburban Oregon, that is already the case, and it's quite convenient to be able to walk over to the nearby grocery store whenever I need something.

It may be true for US but in Europe lots of cities have functional public transport and are dense, so you aren't limited in any way. Lots of people use trains here to get to the city, where I currently live, to work. So their commute is about 50 km but with train it is 30 min.

Does that not limit you to only working at places that happen to be near a train station?