Judging by the current champions of UFC, most of them are not really wrestlers or BJJ artists. Sure they have trained these disciplines, but it is not the way they are winning with and their main art. If we examine the top 5 of every weight we are getting split in 50-50. So your argument is not really standing much weight. The same can be said about every stand up fighter it seems, just by training a bit of wrestling and BJJ they are very successful.
In addition keep in mind not a single one of the strikers in MMA is actually a top of the top striker. They are good strikers, but just a few of them may make a career in kick boxing or boxing. So back to my point a pro boxer unique as Maywheater in his physical prime should, given the time to practice at least an year should do fine in the cage.
Nonsense. Have you ever actually grappled a day in your life? You don't just do a bit of it and then be able to compete in the UFC.
Stipe is an NCAA Division 1 Wrestler
Daniel Cormier is an olympian
Michael Bisping is a BJJ Brown Belt (who trains with high level grapplers every day to stay sharp)
Tyron Woodley is NCAA D1
Conor McGregor is a BJJ Brown Belt (who trains with Gunnar Nelson every day)
Max Holloway is the rare exception, he's only a purple belt but he's still trained BJJ for seven years... Jose Aldo before him was a high level BJJ black belt who just rarely used it, and had the best defensive wrestling in the game.
You seem to be under the impression that if someones not shooting for takedowns they're not using their wrestling. You do realise that the only reason that Conor McGregor and Michael Bisping are even able to strike is because of how good their defensive wrestling actually is.
Floyd Mayweather could train for a year, and it still wouldn't make him a top level MMA fighter, he wouldn't understand how to defend the many takedowns that an experienced grappler would try out on him. He wouldn't understand all of the many angles that an experienced kicker could get him from, and the shoulder roll defence that he specialises in doesn't work in MMA because someone can just kick him in the arm every time he does it.
Mayweather wouldn't beat Conor in a kickboxing bout, let alone an MMA bout.