Driverless cars and public transit will not fix the problem of having to spend an enormous amount of money on infrastructure caused by a lack of density.

or energy moving vehicals & people such great distances

The problem with nice suburbs (Arlington and Duxbury both qualify) is that they're inherently exclusive. They are racially homogeneous, have median incomes at least 25-50% higher than average, and have nothing to offer young adults.

I'm incredibly thankful for my privileged upbringing in a similar suburban community, but none of my peers could leave fast enough.

Yeah, the racial homogeneity is the biggest downside in my experience. It's the one thing I really don't like about Duxbury. Wish there were a good solution.

I find the other problems more ambiguous, though. High median income is almost axiomatic: people with means will choose the nicest places to live. That doesn't bother me much at all. It correlates strongly with lower crime and a stronger focus on education. And maybe "nothing to offer young adults" is actually a feature. I think young adults as a rule should leave their hometowns, travel the world, explore and experiment and do brave and foolish things, learn from their mistakes and get some perspective.

I'm not sure any one [kind of] place can be great for families with young children, and for young adults, and be economically and culturally diverse. Absent the option of such a utopia, as the father of two young girls I'm always -- and unapologetically -- going to optimize for proximity to other families with kids, safely walkable/bikeable streets, and excellent schools.

Respectfully, Chris