Yeah totally, I think those are all things to consider. I'd also guess a factor of young single people sharing households is due to limited supply and high cos

Yeah totally, I think those are all things to consider. I'd also guess a factor of young single people sharing households is due to limited supply and high cost. If it was affordable to have your own apartment, more people would do so. The roommate situation is partly (though not entirely) a symptom of failure to build. You can see this when you compare regions, where I grew up (western new york) housing is super cheap even though there's a lot less economic opportunity. Nobody I know from high school that stayed there lives with roommates. Many have bought their own (nice, new) house for ~150k. That house in the bay area would be 3 million easily. So while I agree there are confounding factors at play, the housing supply issue is so extreme I think the others are largely rounding errors.