It literally isn't possible for every fighter to reach their maximum potential. In every fight someone has to win and someone has to lose lmfao
Fighters should be reaching their potential (or close to) BEFORE they get to the UFC. Once in the UFC it's a proving ground, if you can't hang then go back to regionals until you can. And a lot of the reason fighters are forced back to regionals is because they didn't develop enough before getting to the UFC (the premier fighting organisation/the big show)
From a betting perspective I hate the way prospects get free wins on the way up because it means more squash match odds and less fights at evens. Yeah there's money to be made off fading fighters who get these astronomical odds on the rare occasions they don't deserve them, but it's so much more fun to cap matchups that are legitimately even (or close enough to) as opposed to Khamzat Chimaev v John Phillips