It’s true that a certain demographic of younger people don’t seem to mind living in high density areas, but, just for another frame of reference, all of the many young people we know who are our kids’ ages, professionals, married, in relationships, or otherwise, and have or want kids, without exception, would like to have SFH’s, as our kids’ have found they prefer after moving into their own homes.
From that perspective, many are unable to get what they really want, and it doesn’t look like that situation will improve going forward in CA–especially in SAN–per the scarcity of land.