Our dreams are much more abstract and honestly we're complex than other animals which explains our adaptability, but humans have higher intelligence than other animals so when left to free reign wander we come up with quite the shit. other animals dreaming ig also suports this in a way, but their conciousness have less to work with in the first place, which means they cant learn as much/ be as adaptable. lucid dreaming wouldnt be optimal because then you wouldnt actuallly 'learn' from your dreams, they would just be a hevan too you. people dont remember what they dream because evolutionalistically this would fill up their brains too much, and it is my opinion that when you encounter something you went through in a dream, be it a conversation or a catastrophe, your subconcious will kick in and sort of guide (?) you through it without active recollection of the dream. also basically all poeple cannot remember dreams, not just a few, but this is the weak end of my theory. also this can be applied to other animals not just humanns. sorry for how choppy this is lmao