It is in fact a very interesting question for speculation. I can see why some downplay or even deny its significance for if China had not joined the communist camp, there would have been no need for this war. And joining the communist camp might neither be necessary nor good for China - a view I still hold today.
Yet, in this scenario, the Soviet Union would have been China's enemy, likely a more brutal and constant enemy since it was China's neighbor. Yet the Soviet collapsed in the earlier 90s. But this wasn't something one could foretell. Or, had China not been allied with the Soviet, would the Soviet still collapse when time was due? Or, when?
I agree with Li's observation that the collapse of the Soviet had deeper reasons, but similar reasons can be observed in today's US... ! I think that was why Putin mocked the US : All the US now needs is a revolution.
At the end of the day, we can only respect what has already happened, and value the past deeds in their spiritual dimensions. In the case of the Korean war, the Chinese soldiers did show a majestic, triumphant spirit which was particularly precious given Chinese people's bitter experience since the opium war.
