I do agree that one contributor to the housing crisis in many areas is the lack of SRO and boarding houses, which used to be much more common at least in urban areas. Those are all largely gone now, and they used to be common entry-level housing options for young singles.

If I owned a house would I object to the neighbor taking in a boarder or two? No, but I could see being unhappy about them moving out and turning the house into an SRO rental, especially if those tenants created a nuisance in the neighborhood. Same as a problematic Air BnB.

I think a good compromise might be allowing SRO/boarding if the owner also lives in the house. That is what my town is discussing for at least some residential neighborhoods.

SROs should also be more often allowed in already multifamily/high density residental areas.