The US conquest and occupation of Iraq were one cause of its economic weakness, which is enabling China to move towards dominating the world.

I think that its plutocratist decadence is, however, another cause. (The two are related.)

If this were no more than a matter of competition between countries, I would say, "Let the (most capable) country and system win." The reason I don't say that is that China would impose a totalitarian hell.