It's also part of Autocrat 101 to start a war - or at least generate a crisis - when you're facing a lot of internal problems to which you don't have solutions.
I would point out first that you don't make your name in academia by agreeing with the general consensus. Make big predictions like this, you get attention and engagement within and outside your professional circle. If you're wrong, easy enough to say that what you said didn't come true, it was because X or Y changed. If you're right, you've made your career.
The idea that a "economic, military, and societal collapse" of the PRC somehow wouldn't create the geopolitical equivalent of the asteroid that killed the dinosaurs is...well, wishful thinking. If that were to happen (I seriously doubt it will) then our need to be engaged in the western Pacific is greater, not lesser, because it's going to be an absolute mess. The most likely result of such a collapse would be the country backsliding into warlordism, China's normal mode of government for most of its history, which is always fun when you've got an enormous army and a nuclear arsenal.
I agree with most of this, but a couple counter points to play the devil's advocate.
Regarding the first bolded bit above, autocrats in history do not have a track record of starting wars with near peer competitors as a way out. They have (as far as the examples I can think of) traditionally picked on the little guys. IE, Hussein vs Kuwait, Putin vs Ukraine, Hitler vs Jews (and weak Euro neighbors), etc. Are there any examples that should make us fear China attacking us?
As for the second bolded bit, the only example I can think of that is similar to what Ziehan is suggesting might happen in China is the fall of the USSR. Before that happened, everyone also agreed with you that it would be catastrophic, yet they were all pleasantly surprised.
That said, I agree that China should remain our focus. The middle east is no existential threat, and as far as attaining our desired end states over there, I think time has proven our actions do as much harm as good. Meanwhile, Russia has proven to be a joke backed up by nukes, so our military is completely unnecessary in Europe. Focused on China is exactly where it should be, no matter what may come there.