Many sects have been founded with certain philosophies and virtues in mind aside from martial arts being its primary trait. The Beggar's Union are compromised of poor heroes, Shaolin is compromised of Buddhist followers, many sects are merely just regional badasses that bully their region while trying to craft a good reputation.
Despite all the differences in leadership ability, founding principles, or regional location, it seems that the ONLY thing that dictates whether a sect succeeds or not is if you have the most powerful/one of the most powerful people as your leader.
The Beggar's Sect numbered in the hundreds of thousands, but they quickly got demoted to a third rate sect in a short time span once they lost their Greats level fighters in Hong Qi Gong/ Huang Rong (Guo Jing).
Quanzhen became THE top sect of the martial world and of course they had Wang Chongyang.
Wudang only had a legacy of tens of years before they were equals and even surpassing the other great sects with hundreds of years of legacy.
Zuo Lengchan was the leader of the 5 Sword Alliance and had by far the most powerful sect, and of course he was the most powerful.
The Ming Sect flourished when they had Yang Dingtian and Zhang Wuji, both of whom were the most powerful active martial artist in their age.
Shaolin/Wudang/Sun Moon were the top 3 sects in SPW, and of course they happen to be the top 3 most powerful people.
Does the average sect joiner really care that much about belonging to a sect that houses the most powerful person, when they know they will never see them and never learn anything from them most likely ?