In fact the genocide only stopped when a bunch of unsophisticated American (and Russian) farmboys rolled in.
It was also an economic disaster. Surely that contributed.
(Its aftermath was a necessary transition, that happened to be disastrously mismanaged.)
The current proponents of new "realism" who claim that regional empires will co-exist in peace would do well to study the causes of WWI.
Yes, for some definition of "works well" but the population has to be tightly controlled. It's why the oligarchich elite is so enthused to build out the surveillance state at the same time.