Let's face it, he's easily the biggest, most talked about athlete in all of MMA. No other name generates interest/discussion in the MMA world than Mayweather, hence the concerted effort on the part of the likes of Rousey, McGregor & Zuffa to use the Mayweather name to promote themselves & the UFC brand. I honestly think the UFC suffers even worse than boxing post-Mayweather. Zuffa's marketing seems so short-sighted, so lacking in any real long-term planning. Mayweather's already got one foot out the door; he's not likely going to be around in time to help promote the likes of Paige VanZant. She'll have to hope Gennady Golovkin's become a big enough name/attraction by that point.