If we are looking at what's in are basic genes as a marker on what we should be doing, I don't think we should be messing about with fusion. Or fission come to think of it. I agree loneliness and mental health are big problems today however don't think the answer is having an adversary to motivate yourself.

"If we are looking at what's in are basic genes as a marker on what we should be doing, I don't think we should be messing about with fusion. "

Why?

I didn't say we should live stone age style. And using technology is very akin to our genes, afaik. So I don't see any problems with that. What matters more than the tools are the social interactions I believe. And there we could do better.

I'm not sure if the Earth is large enough to distribute 8 billion humans into sufficiently separated small groups, and such a scheme isn't even on the political horizon.

I didn't say there need to be a big space separation, nor clearly divided groups, just that the general people you interact with are in general familiar and not randomly strangers who change all the time. So a more tribal way of living in the cities is possible, I believe.

But .. actually there is also enough space on earth left ... poplated areas are very dense compared to big open lands.