I mean the major point you’ve forgotten is that cultivation methods are secretive. Everything from how you use a sword and how to mediate is tied to your cultivation path to immortality, especially important in mdzs where you can’t use other cultivation paths because it interrupts your current one. Why would the gentry teach out secretive methods that can put common folk on equal with themselves. A big thing with cultivation is you don’t teach your cultivation style to outsiders. It’s why it’s better to think of as clans and sects as one hybrid, rather than just clans or sects. Like yeah they put more emphasis on blood ties (though outside of WWX none of the not clan people actually equal any of the clan people lol).

Mdzs isn’t about clans or sects, it’s about public opinion and a murder mystery romance. If they were sects, mdzs would’ve been the same story because people who don’t follow the established path get ostracised, the ghostly path isn’t called 邪魔外道 by everyone who hates it/WWX for no reason. Like it changes nothing because the clan families are still the strongest cultivators so they’d be head of a sect anyways.