My understanding is that it's pretty common on the US coasts (i.e. the major metros where housing is super unaffordable). I imagine it's a self feeding cycle.

My understanding is that it's pretty common on the US coasts (i.e. the major metros where housing is super unaffordable). I imagine it's a self feeding cycle. Young adults can't purchase homes, so their parents cosign and give a big down payment. Then sellers are able to ask more because wealthy parents are backing the sale, which just makes housing even more unaffordable.