Would IT be a viable solution though? Take away the side effects and there are some fundamental flaws in the design of this goal
1) there would be no reproduction so humanity would die out when those in the dream age and wither into nothing.
2) how long can the tree keep this up without someone inside eventually realizing they are in a dream. Ever heard of Lucid Dreaming, the knowledge of knowing you’re in a dream? At some point a number of these dreamers(if not all at some point) will realize something is wrong. What happens then? Are they stuck in their “perfect” world knowing it is fake?
As far as humanity’s end. That’s some rather dark line of thinking. We are not only capable of greed and destruction we can actually do much to live and improve nature and the world around us. We just need to mature more and evolve as a species. Evolution has never been a clean and neat process. But despite all the hurt, pain, and suffering in the world I still have faith in humanity. Call me a dreamer if you wish (no pun intended)
I’d rather have a dream than to give in to despair.