> We are building massive 3-4k sq. ft. homes for families of four [...] Everyone has their own bar, restaurant, theatre, and community center. [...] the required square footage per person drops by huge amounts when people can walk to nearby community centers, restaurants, kitchens, theaters, and bars.
Most families don't live in 3-4k sq homes. The average newly built house today is a little over 2k sqft, and most houses are not newly built. Unless you are seriously stretching their definitions, most do not have their own "bar", "restaurant", "theater", and "community center".
A house or apartment should follow a kind of "fractal" pattern that mirrors private and public spaces that encircle it or that it contains. A town should have a town center. This is the public square. For towns large enough, you'll have neighborhoods with squares or parks that are the public meeting place for the neighborhood, but more "private" in relation to the town. Each neighborhood is divided into housing units. An apartment building should have a public space for the apartment buildings, like a courtyard, that is proper to the building, but private in relation to the neighborhood. Within each apartment building, there should be a living room + dining area that function as the public space of the apartment, but which is private in relation to the apartment building (the same principle holds if we replace "apartment building + apartment unit" with "individual house"). The ultimate private space is the bedroom.
Of course, this is idealized, but this is a principle we see in traditional architecture and one that makes sense and respects human nature and supports human flourishing instead of trying to impose some weird, inhuman, Procrustean invention on people to check off some boxes. The things you mention, like bars, restaurants, theaters, and community centers, would appear chiefly in town and neighborhood centers. But they don't replace the living room, the kitchen, and the dining room.
EDIT: Ah, and I would define "neighborhood" in terms of walkability. I should be able to get to the town square by walking in a reasonable about of time.