Mayweather is one of a handful of boxers who are still UNDEFEATED.
Maybe he wants to go down in history as being undefeated rather than risk a possible lose (even if it’s worth relinquishing $100 Million ). After all, he’s rich enough already...
Just my guess...
You're guess is spot on. Mayweather's ego couldn't tolerate a defeat and he's turning down a min. of $50 mil to prove it.
In his own mind he's already a loser!!!
Going undefeated won’t help his legacy if he didn’t fight his biggest competition.