People are inherently ambitious; who doesn't want to stand out?
However, the ossification of class resulted in the blockade of social mobility, stripping many of the opportunity to ever stand out in their lifetime!
Daqian was an imperial dynasty with rigid class stratification and blocked channels for upward mobility.
Founded by a foreign ethnicity, the caste system was stringent, and the Han people were third-class citizens.
The obstruction of social mobility was most evident in the severing of the path of imperial examinations. If a Han person wanted to become an official, they had to find a good master, become attached to them, and gain power as house slaves.
This was a display of insecurity from a foreign ethnicity.
The base of the Han people was too large. In contrast, the Mulan people were far fewer, and they feared that one day the Han people might gain power and overthrow them.