I've seen a few posts suggesting that related communities should be merged, but I think their current fractional states help to mitigate some toxic behaviors.
There's more accountability in smaller groups, and less impetus for negative attention-seeking behavior.
I also wouldn't want them merged. But I would find it great if I could kind of curate my own "front pages". E.g. creating a page for myself called "Technology" and adding all the tech communities that I follow to it so that I can see all posts in one place.