“And they did SOME conquering successfully, or we’d never have heard of Sun-Tzu”
No.
That was all just inter-Han conflicts within a fairly small geographic area of East China.
China expansion, to the degree it expanded, was due to being taken over by outside forces.
Well OK, if we go with that explanation, what happened once these “external forces” began to rule?
Didn’t they, too, winnow through the culture, keeping what looked promising and chucking out the rest?
A philosophy refined by winners is probably going to be bent on winning, correct?