I think that the classic "western" approach to family residences is becoming more obviously damaging to everyone involved as time goes by. Growing up in a multi-generational household is a significantly different experience compared to having either two parents - or having one primary parent and a bread earner. Being exposed to more diverse opinions on a regular basis is probably healthy - seeing authority as imbued and transferable instead of being the exclusive domain of a parent is probably healthy - living in a household with more access to people (less technology filling the gap) is probably healthy - and living in a household with lower overall stress (since there are more people to bear the burden) is probably healthy.

I think single children end up doing poorer for much the same reasons that older siblings serve to lessen the reliance on parents while also being imbued with trust and responsibility... but, I think having more adults present as "caretakers" is just a good thing. So, even if we keep nuclear families internally - it might be beneficial to children to open up more community trust for communal custody of children's development.

I grew up an only child[1] and I have a lot of pleasant memories but I especially treasure some times I went off with a random Aunt, or a random neighbor and got to watch them for a day do their art stuff, or go for hikes in a different way - it helped shake up my mental monoculture. I had friends that grew up in multi-generational households but didn't myself, and it was quite a different experience being over there... learning that just because parents were away it wasn't anarchy - getting to interact with different adults different days and doing different activities that interested them.

I really think the nuclear family approach could use some real improvement.

1. Essentially... both me and my brother were only children at 13 years apart.