Bang on points once again!

I couldn't help but be reminded of archaeologist Joseph Tainter's argument in The Collapse of Complex Societies as I read through your post. That declining marginal returns serves to lead to collapse throughout pre/history does not bode well given we have increasingly encountered such a decline when it comes to our most fundamental resource--energy--that underpins virtually everything we do, but especially in a globalised, industrial world where few retain the skills/knowledge to survive without its products, supports, and conveniences. And once the power grid fails, all bets are off as to how everything plays out.

As for the West/East 'survival', also of note is his assertion that peer polities that get caught up in the competitive sprial of outmanoeuvring each other tend to collapse together because of their tendency to keep 'investing' in competitive actions despite increasing 'costs' due to diminishing returns on their 'investments'. So, when the West 'collapses', pre/history would suggest that the East will do so as well--both having dug themselves holes so deep they can't even see the sky anymore.

And all of this doesn't even touch upon the predicament of ecological overshoot that has led to an extremely tight bottleneck for our species...