They are _a_ solution, for sure. They just aren't _the_ solution. I'm not sure dense cities are _the_ solution either, especially as more and more work is done remotely. I think humans weren't meant to be cooped up in a tiny concrete box. I like my backyard, and the forest behind my back yard. One size does not fit all, and it's not really feasible to tackle lower density living setups with "public transport", at least not in a large country like US. Moreover, this isn't "either-or" thing. I'd love it if my car could drop me off at the train station and then parked itself at home, then picked me up on my way back.