Where would the money for production, marketing & distribution costs come from? How would they financially be able to deal with never ending problems and landscape changes that every business has to deal with - especially one that's entertainment content based like an MMA promotion? What about making business relationships, getting channel deals and breaking into new locations, let alone booking the current venues? Unless you're planning 1 show at a time - which has proven to not be successful - you'd need some serious financial backing for a 5-10 year plan which would then feed off the money the events would make. And so the fighters wouldn't be getting all of the money anyway.
And since this whole thing is about money - how will it not turn into a circus anyway?
Reason why UFC isn't a real sport is cause there's no tournament structure. If this Ultimate Communist Championship you're proposing wanted to make things fair, they'd do the rankings properly and rarely would the champ be the one drawing money. And are you naive to believe that if you got a Conor 2.0 on your hands, you'd have the restraint to not push him above everyone else? If the numbers showed that with him as champ you could make $100 million, but doing it by the book would only get you $10 mill? Would you really be cool with that? Would your fighters be cool with that? Some would get jealous and crave the same push (even though they just don't have what it takes, as far as marketing to audiences goes) while others would just want him on a card, so they can get paid more and go home. You'd have a civil war of ideologies.
I'm using simplistic language here, but the problems would be tremendous. There's no way a shindig like this could exist. Best bet is to clone UFC and have a less greedy Dana White in charge, but... why would he do that job then? Settle for less when he could be getting more? Right now, if WME decided to pay Dana White much less and give it to the fighters - he'd leave and make the same money somewhere else. And WME would need someone else - equally as qualified, respected and capable to do the job. Which might be realistic, but that person would also reach their sealing at UFC and leave for something better. And to constantly have no constant order at the top would just make things dodgy.
This is getting too fat, sorry...