Spending time in parts of Latin America or western Europe or east Asia and then coming back to the US, you can see a lot of ways in which we've built loneliness into the fabric of US culture. It goes beyond car culture. It's probably illegal to build a cafe within walking distance of your neighborhood or into the first floor of your apartment complex. Americans get an idea of how bad we have it when we go on vacation…
I wouldn't trust a cafe built into an apartment complex. I'd expect it to be low-quality, over-priced food placed specifically to try and make a quick buck off people who don't know any better or who physically can't get somewhere better.
You're right that it goes beyond car culture (and zoning laws are part of car culture), but I think it also goes beyond zoning laws. A lack of a social contract between people (individually) and businesses these days is probably involved, too. All these things are interrelated.