if you took the world and seperated its humans by intelligence, the “idiot” group is going to be much bigger than the “PhD” group. Like…by a lot.

No.... you'd have a bell curve. But even that assumes you have a single good measure of intelligence.

I kind of agree with the rest of your post, but I would have worded it a bit differently, emphasizing that people who found it difficult to start using Lemmy might still be worth having around. Also, I don't think "as large as Reddit" or "small niche unknown" are our only options.