When I was in my late 20's, early 30's I was able to get married, buy a house and start a family. It was almost automatic. That's just what you did. I found out after buying my house that it turned me into an adult who was invested in the system. Home ownership feels like the bedrock for a stable and sane society. I worked hard to attain and keep what I achieved.
Today young people are priced out of the housing market and are hesitant to have kids because the future appears grim. Why get married under these conditions? Why work hard? There isn't much reward so it doesn't sense to waste your time that way.
I never hear my theory discussed by wealthy people and their publications because they'd rather blame it on something else, especially on young people themselves.