I recommend reading Robert Putnam's Bowling Alone (2000). American civic and social engagement has been declining in almost every measurable way for 50 years now. There is no way to deny this.

The largest contributor according the book's surveys and studies (and I love saying this) is television outcompeting in-person fun. Car dependency is a factor, but IIRC was factor #2 or #3. While this ranking was true at the time of publication, I would wager that time spent on "screens" is likely factor #1, #2, and #3 now.

Please read the version with the 20 year update: https://www.amazon.com/Bowling-Alone-Collapse-American-Commu...

I would wager that many people are fleeing their hometowns to socialize in cities not because they're walkable, but because the density of people increases, allowing you to have better odds meeting real humans who haven't been lost to the allure of the indoors.

The average American watches 4 hours of television a day, and I don't think that includes cell phone web scrolling.

I don't think you can have a realistic conversation about American physical or mental health without centering this fact