You make it sound like demo-collapse would be a bad thing. Have you been outside lately?
Demo collapse is pretty much the solution to the problem. Nature will reassert itself, the unfit will die off or be killed off by their fellow liberals who by definition are likewise unfit to survive and then the strong/intelligent rebuild.
If you look throughout history, that cycle has asserted itself over and over. We are not special little snowflakes immune.
You seem not to put value on human life, so I’ll just point out that you will not like the economic consequences of population collapse.