There is some data out there (that I read like 20 years ago and can’t find anymore) that tested two groups of juvenile rats. One group lived 24/7 with mom, and the other split time between mom and their buddies, playing and doing dumb young animal shit.
The scientists discovered that the rats with mom had a less developed brain vs the ones who split time. They posited it was due to the split time rats having to navigate friendships and conflict, forcing their brains to develop more complex neural pathways.
Extrapolating this to humans you can see what the repercussions would be (and in my experience, has become).