What allowed the Mongols to conquer vast territories in China? Why was their power over this country short-lived?

We are talking about the events of the XIII century, from 1215 to 1279. They managed to conquer huge territories for the following reason:

Discipline in the Mongolian Army. For the flight of one soldier, ten could be executed at once.
The size of the Mongol army, especially the cavalry.
Rapid mastery of Chinese stone throwers and other siege vehicles.
China did not exist then as a single state. The Mongols fought the Khitan, Tanguts, southern Song and other parts of it for about 60 years.

The power turned out to be short-lived due to the uprising in China in 1368 and the collapse of a single huge empire of the Mongols.