Housing is quite affordable for young couples in most US minor metros. Trying to squeeze into a few major metros is a terrible choice for young people who want a decent life.
I used to live in a small provincial "city" of 150.000, 250km from the country's only big city. People often mocked it was the graveyard of ambition. But to me it really felt like that. I hated living there so much.
If remote work is a possibility, or big cities decentralize a bit, that makes sense.
We've seen during COVID, if people can move from San Francisco and keep their jobs, they will do it.