RE: Will We See A Return of the Multi-Generational Household?
I think we will see the move to multi-generational households in urban areas due to the lack of expansion, cities can only get so big and real estate becomes premium. If people want to build the generational wealth they would invest in the family home instead of going out to rent. Not having to commute as you mentioned would also see people remaining in one home.
As for those in Rural areas or ones who move out to homestead a multigenerational home makes sense since you rely on your little tribe to keep the ecosystem going and it's not about outsourcing tasks to companies or individuals. You make your household work through the work of those in it.
I think its a very interesting shift in dynamic as a lot of people will be torn between valuing their personal space and the freedoms the previous generations had as we revert back to multi-gen homes.
I think that today, in developed places like the US where multi-generation is no longer the norm, the places we do still see it are largely inner city urban poor for the reasons you mention (although whether they actually have ownership of the apartment or not).
In Ireland during 19th century it was huge families in large Georgian tenement buildings (which you see all over Dublin today).