I could be underestimating how constantly drunk Stalin was, but I like to think he wouldn’t engage in battles that he has absolutely zero chance of winning.

The US public was tired of the Korean War in 1953. How would Stalin estimate, do you think, the American public supporting an unprovoked nuclear assault and invasion against a much larger and more dangerous enemy in Communist China and the Soviet Union simultaneously, with probably the withdrawal of the entirety of our major allies from the war?

A world where China has been taken off the board is a world where USSR has less allies and is surrounded on all sides.

... which is exactly why the USSR would not have let China fall at that juncture. "Just let your enemies isolate you, just stand by and do nothing" is not a very likely course of action for the USSR.

Any alternate reality where the CCP doesn’t exist is enviable to some degree.

Fuck no. There are always worse scenarios on every aspect of reality. That's the same kind of campism tankies use when they say that "any" outcome to mass unrest is better than the status quo. It reflects a distinct and severe lack of imagination, or else an irrational disposition towards the status in question that is entirely divorced from actual moral or strategic concerns.

We should have brought the entirety of China to a knee when we could have.

...