1). Better Money
Brock Lesnar has never been motivated by the grind of the industry. He's never cared about performing week-in, week-out, travelling continents and selling out house shows.
Brock Lesnar is a star attraction who shows up once in a while, lazily throws around faceless bodies, collects a fat paycheck and returns to hibernation.
And you know what's the worst part?
He knows that he can get away with it.
Brock Lesnar is a prize fighter and every roided-up fiber in his being (oops?) knows it. And for someone like that, a one-off super-fight in the UFC is a guaranteed bumper payday that even WWE can't match up to.
So when Jon Jones called out Brock Lesnar after making a triumphant return at UFC 214, the allure to cash in on a bank-breaker was too much to resist for the behemoth.
No sooner had Jones' mic dropped onto the Octagon floor, Brock Lesnar responded; "Be careful what you wish for."
But we all know what Brock Lesnar wishes for more than anything else, don't we? And if he fights Jon Jones in a chart-bursting UFC super fight, he's going to get paid more for 25 minutes of work than he does in a year in the WWE.
It's quite a no brainer, really.