Though you mentioned banks as something that is still pretty far away. A few years ago I was self-employed, collecting old-fashioned checks (it was slow moving to digital) and I had to frequent a bank once every week, two weeks at most since I had to deposit checks that were in USD and my bank in here Canada couldn't yet do that via an ATM. My nearest branch was walking distance but I still chose to drive because it was a 20m walk, 5 - 10m bike ride or 1 - 2m drive. Since it was such a big chore to have to go there in person, I opted for a car more often than walking or biking.
I think that at least some of what drives these discussions is congestion and parking in major cities. I can't stand driving in downtown Toronto. But in my mid-sized city I really don't mind driving 5 - 10 minutes vs having to double or triple that to walk or bike there. Add the benefit of personal space and a trunk to carry groceries in and I can't see any benefit (beyond maybe environmental impact) to a "15 minute" city in a medium-sized city where traffic congestion is not really a thing and a short car ride will halve your 20 - 30m round trip.
City advocates claim that North American suburb existence requires you to plan your grocery trips and buy lots at a time, vs the "benefit" of city life where you can run to the store to grab milk if you're out of it. The idea of going to a crowded grocery store is such a chore that I welcome any strategy that gets me going there once a month or even less if at all possible. The idea of running to a grocery store, even if it were a block away, for a single item or two is nightmare fuel given that the trip could be avoided all together with the smallest bit of planning, whether walking or driving. So how do I accomplish buying a month's worth of groceries if I have to walk there? Whereas, if I have the choice to drive or walk, I can decide how much to buy at a time and how often I want to go. Big win for cars.
Another drawback to the "15 minute city", from an extreme introvert's perspective, is that the closer things are to your home, the closer PEOPLE are to your home. It actually bothers me if I'm sitting on my couch reading a book and I can hear people walking by on the sidewalk. When everything is close by, so are people. I really like living as far away from people as I reasonably can. A vehicle becomes a necessity with remote living.