Mayweather vs Berto tickets struggling at the box office

Jayne Kamin-Oncea-USA TODAY SportsShowtime and Mayweather Promotions have done an admirable job of pushing Andre Berto as a quality opponent for Floyd Mayweather, but the fans aren't buying it ... at least for now.

Literally.

"The Telegraph" reports that tickets remain readily available for Saturday's (Sept. 14, 2015) clash between Mayweather and the aforementioned Berto inside MGM Grand Garden Arena in Las Vegas, Nevada.. This is despite the fact that -- even at their most expensive -- the tickets are a fraction of the price of "Money's" last effort opposite Manny Pacquiao.

There are a few potential culprits for the flop, likely working in conjunction. For one, Berto is not a threat. He's a…