Many people can't drive because of disabilities either, and cars make spaces much less safe for many people with certain disabilities as well. For example, my sister dealt with random spells of vertigo for a while, and thus her driver's license was suspended as a result. Car dependency made life significantly harder for her once she was no longer able to drive because of it. The one thing that ended up being a lifesaver for her was an e-bike, as it could handle the steep hills in her neighborhood and get her to the nearest grocery store a few miles away. Even with that, her neighborhood still has almost no bike infrastructure, which make biking to the store much more hostile than it should or could be.

Similarly, there are plenty of people who can't walk or bike very far and can't safely drive (like elderly people) for whom public transit is a great option -- provided we as a society choose to build enough public transit to serve them, of course.

Point is, the only transit system that can serve everyone is a multi-modal one, where there is bicycling, walking, public transit, etc. all layered together.