A lot of great empires through history did not collapse. They simply stagnated. Stagnation can go on for a long time. The Ottoman Empire stagnated and fell behind Europe. China itself stagnated for hundreds of years. Collapse really came from the embarrassment of being too weak in one engagement after the other with great western colonial powers.

Of course we don’t live in that kind of time so stagnation carry less risk. I suspect China’s future is a bit like Japan. In the 80s we thought they would take over everything. They expanded and free like a rocket until they didn’t. Japan didn’t collapse but nobody sees it as a threat to the West anymore.