I would argue that because China was a large country, it didn't have the same geopolitical issues that European countries did.
European countries were much smaller and because of this there was a fair amount of international trade going on across their borders. This trade promoted the sharing of ideas and because these countries were small and so close to each other, it also fueled a military arms race.
China did not have the same issues
There's also a saying that goes back to the Sung Dynasty. "Just as you do not use good iron to make a nail, you do not use a good man to make a soldier."
Throughout a good part of China's history, the military has been seen as a repository for wastrels, gamblers, and thieves. During the Ming period, there was a lot of corruption. Some officers hired out their men for labor. Others falsified their records and pocketed pay for soldiers who only existed on the books. Still others taught their men to look smart and to shout fierce war cries while stinting (or even abstaining) from any military drills.
Such environments were simply not conducive to innovation and far too many of the senior officers felt no compulsion to make any changes or reforms.
paints a legend from the Trojan Wars.
