That number is typical for a big fight in Vegas. It takes the news media and the like to create cross-over interest in a fight. Olympic known fighters have the advantage when it comes to being a cross-over star. Promoter's don't have the formula on how to create a cross-over star although that is exactly what they want everyone to believe.
No one ever expected Staples to sellout (over 20K) for Margarito / Mosley because Mosley was getting old but it's a huge Latino market in Los Angeles. Black vs Hispanic makes a lot of drama, is as good a guess as anything that caused it to sell so well.
Black vs Black in a black location? Not really a lot of drama and again it is only a guess at what is not selling.
The proven best seller is the Classic Good Guy vs Bad Guy, but the promoters have to advertise. I have seen nothing for selling Bradley/Alexander on regular media, so it's not surprising.
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