Either way, McGregor might be the greatest evangelist for any sport since Muhammad Ali and boxing. It's a big reason he ranked as high as No. 25 on World Fame 100.
For a decade or more, people from the world of MMA have been telling anyone who cares to listen that their sport will, one day soon, knock boxing off its perch.
It hasn't happened yet. In fact -- while boxing is going through a healthy patch and absolutely flying in the UK and Ireland -- The Ultimate Fighting Championship (UFC), the Premier League of MMA, is going through a slump.
One of the main reasons is that McGregor has realised he can make more money in boxing. Between Dec. 2015 and Nov. 2016, McGregor headlined four UFC shows, all of which garnered more than one million pay-per-view buys.
Of the four UFC shows so far in 2017 -- only the most recent UFC 211 in Dallas garnered more than 300,000. And that event, despite being headlined by heavyweight champion Stipe Miocic, wasn't even a sell-out.
It appears that for many fans of UFC, if McGregor isn't on the bill, it isn't worth watching. In his last UFC contest, McGregor became the first fighter in the franchise's history to hold titles in two weight divisions simultaneously by beating Eddie Alvarez.
It was the eighth time in a row that McGregor had either won the performance or fight of the night award.
But for some boxing fans, McGregor represented a strange paradox: a key reason UFC fans loved him so much was because he finished opponents with punches rather than some mysterious hold or choke -- so why didn't those UFC fans just watch boxing instead?
Whether McGregor really believes his talent for punching -- or 'striking' as they call it in UFC -- is on a par with elite boxers is moot. He punches well enough to fool enough casual sports fans into thinking that he can cut it in a boxing ring.
Therefore, if McGregor fights Mayweather, millions will pay to see it. Never mind that sage observers think McGregor would struggle to win an Irish amateur boxing title.
Never mind that veteran boxing trainer Teddy Atlas, on these pages, stated he could train McGregor for five years and still not make him into anything like a contender.
Never mind that Mayweather is one of the greatest defensive fighters of all time and never lost in 49 professional fights spanning 19 years and that he made Saul Alvarez and Manny Pacquiao -- a seven-weight world champion -- look like club fighters.
In short, there is far too much money to be made for the fight not to happen. Before Ali's fight (if you'll forgive me calling it that) against Japanese martial artist Antoni Inoki in 1976, a journalist asked 'The Greatest' why he was choosing to "demean" boxing.
Ali replied: "Six million dollars, that's why!" Remarkably, Ali earned the same for getting his shins kicked to smithereens in Tokyo than he did for fighting Joe Frazier in the 'Thrilla in Manila' in 1975.
