I've been reading about some of descriptions about "Mongolia Proper" during Yuan Dynasty, when the Mongols were supposed to be on top of the Empire's hierarchy. But instead, it turned out that ordinary Mongol herders lived quite miserably, when the spoils of the empire was not given to these ordinary Mongols, but the burdens of maintaining the empire fell on their shoulders.
An ordinary Mongol herdsman had to provide horses, weapons and services during military campaign as well as for the noblemen's recreational hunting. He has to work, unpaid, for the Great Khan's postal system, knowing how hazardous riding across the steppe in those days. No help arrives when a snowstorm kills his sheep, and in the end, he was reduced to selling his wife and children to survive, often to the Semu, the Han and the Southerners.
The thing about a Classical Empire was that when its boundaries grows, the burden its core ethnic group had to carry also grows disproportionately. And thus an Empire's hour or glory might be the most unbearable one for it primary subjects.
This was not quite the same as modern imperialism, when, say, a worker in Victorian Britain might be benefited from its growing industries, which were in turn made possible by the raw materials provided by Britain's colonies.
Did such impoverishment happen to the Empire you are currently reading about?