If the benefits of staying apart are perceived and/or work better than staying together then people will stay apart.
In the first place, the idea of "sticking all together" should not remain unquestioned. Leads United is a game of words related to football, not MT :)
My main answer to "why, oh, why aren't we all in the same boat" is instead simpler: sick legislation. In my place all you need to turn on a sanctioning body into a personal franchise is a general assembly and a handful of brainwashed followers.

The core problem:
- the general assembly should function democratically
- this creates the huuuge problem: "the boss introduces clubs of semicontact or worse -> all these are owned by friends of his -> general assembly turns into a voting machine for his clan"

A first solution is to split management and obviously budgets on a-b-c classes and devise a way to make all work together for the big picture but have decision power where their level belongs.

Still remains valid the question "then who promotes a club from c area to upper areas". In my place, the boss of the federation (whom no one works with actually in the A class area) is soooo careful with licensing profesionals that actually no one owns a license. Answer is more complicated: associations should be led not by presidents and councils but by representatives of strong clubs based upon participation/promotion of events. I dare to say: this is oligarchy, but it remains lucrative. It is preposterous to freeze all the things under a boss and the boss has had "some" activity 35 years ago when he graded 2-nd dan the chimp of his boss :)