That's not been my experience. Technology has advanced such that there are things that used to be expensive that are not any more. However, I don't see more people who are able to live middle class lifestyles. Things like owning their own homes, not having roommates, being able to leave demeaning jobs, only having to work one job, raising a family on a single income, etc.

This doesn't map exactly to "middle class" but it also seems like there's now a lot less ability for people to afford to work in "artist" type careers. It used to be that you could wait tables, get a low cost studio in the city, and work as an artist in the evenings/weekends. Now you have to work multiple jobs and probably still can't afford to live in the city and make art.

That was due to housing abundance, caused by the rollout of the automobile, creation of the suburbs, and abandonment of the cities by people with money.

Unless we have another social & transportation revolution that brings another swath of virgin land online, our best hope of recreating that is to build a lot more vertically in already settled areas, which would probably have to involve demolishing middle class power.