What about selling busses and trains, and buildings bike lanes and train tracks? Loans and cars aren't the solution to loans and cars, but there are solutions.
Plus, money isn’t always the reason people can’t or don’t drive. People may have disabilities that prevent them from driving. Heck, some people just don’t like driving. Improving public transit, biking, and pedestrian infrastructure solves most of these issues, and it’s frustrating how car-centric the US is in most places.
The OP addresses that:
"When people wave off Waymo or bus lanes or bike lanes because car culture is fine, they mean it works fine for them."
I lived in a place for a few years that had a free public transportation network. I can’t tell you how liberating that was, because it meant that I could get to lots of places without owning a vehicle. They even had bike racks on the busses, which meant that you could easily cover the last mile.
That place decided that free public transportation was a good investment. I think many people here would see it as a waste of their tax money. But those people are not low income. They can afford to buy cars. I occasionally hear my coworkers remark about how they would never ride one of those city busses—YUCK. It kind of grinds my gears.
Living in that place made me feel like the community actually cared about me. It made a big impact on how I think about what is worth spending my taxes on. We already subsidize the middle class (roads ain’t free!) and we subsidize the heck out of corporate America. A small slice of those subsidies would make a big difference for people at the bottom.