[pm90]

That could most certainly happen again. Usually the way previous empires have broken up though is by keeping aloof of the rest of the world, resulting in the State not keeping abreast of developments in the rest of the world.

The current regime seems to be acutely aware of this and has been actively spreading Chinese influence (and finances) over the rest of the world.

[megaman22]

Is that really the usual case, or just the narrative of the Qing dynasty?

There's a lot of mismanagement and climactic shifts in the pre-modern period. Often those are tied together, with failures of the hydrological infrastructure. But another common thread is high imbalances in male/female populations, leading to lots of disaffected young men, and millenarian religious movements.