When income is low and housing is expensive, kids stay home longer, renters get room mates, and buyers find partners for joint ownership. It's like that in many places around the world.
When my family was poor, we shared a SFR in Anaheim with my uncle's family. We split the rent and utilities, and was able to save a few hundred every month. My parents worked in low paying jobs at the supermarket and restaurant. After about 6 -7 years we were able to save enough to buy our own town house. We actually looked at Irvine back then but parents said it was too far from work, so we bought a town house in Buena Park with 15-year fixed rate loan.
I stayed with my parents until I was 28, when I saved enough to buy my own condo. Then my grandfather fell ill and needed full time care, so I rented my condo out and moved back home to help out, until he died few years later. Some might say that I was giving up personal freedom and privacy, but if you consider the amount of $ you're saving by having your parents pay for everything from home cooked meals to toilet paper... it adds up. By moving back home I was able to save enough to buy more properties, and let's just say that it has been a profitable decision.
I also noticed that with some Asian and Hispanic immigrants, they use co-ownership to buy homes. My HS buddy, ex-GF, and her friend's family all did that to afford homes in Lakewood and West Covina. Typically they'd buy with a relative and co-own the property. When I lived in Placentia, I noticed a few Hispanic families doing the same.