What he suggests is completely besides public transit, it's about spaces in general where cars aren't allowed or catered to. It doesn't just apply to big cities, but mid-sized and small cities have an absolute dearth of pedestrian-focused plazas. Small towns are extremely hostile to basic foot traffic. There's no reason for this to be the case. In Europe the small town equivalent will have a center where most of the commerce and services are, where cars are completely forbidden. You simply drive into town, park somewhere and carry out your business on foot. It's very nice.

Plazas do exist in the US, but they're rare. Very rare, especially outside of New England. That's what OP is talking about, public transit is a 'solution' to a different problem, and one that I don't like either. See, my biggest problem with urbanism is that it's overwhelmingly focused on building huge megacities, which are inherently unwalkable nonsense. Instead, walkability becomes rhetoric for any mode of transit that isn't a car. I hate that. I want walkable living spaces that are actually walkable, not urban environments where I walk to the train station because the city is too large for its own good.

I don't want to replace the personal car with public transit. It misses the point entirely. I don't want to have to use anything more intensive than an e-scooter to get around the place I live at all. Walking to the train station and riding that for 10-20 minutes to get to the other side of the city sucks. The social problems endemic to public transit in the US are just icing on the cake. Tokyo is a hellish nightmare compared to an Italian commune.