It's only when the generation that remembers the Long March is out of power that the Korean situation could be peacefully resolved as the result of Chinese intervention, and then only if the people in charge of the PLA see that their greed would be hindered by a war on the Korean peninsula. Until those two prerequisites are met, I do not see a peaceful resolution of the situation that would have any pretense of being a long-term solution.

Notice that one of those prerequisites has the implied requirement that the West has actually stepped up and said "We are ready to fight". If China does not see resolve on the part of the US, South Korea and Japan, and a willingness to resolve the situation by military means, China will not be ready to make any significant concession at all. What incentive do they have?

The danger in waiting is that the younger generation may feel that China will be stronger if the West is weakened through war. A war that saw North Korea destroyed but potential economic rivals Japan and South Korea ruined might be an economic boon for China if they let North Korea start something and then step back and not assist, essentially leaving North Korea to the mercy of the US and South Korea.

Plausible deniability is the term I'm thinking of. China is perfectly willing to play a game like that. The question then becomes one of the damage caused by a war now vs. the damage caused by a war ten years from now. The former is certainly preferable to the latter.