Even in black culture most of the fans are white, even in hip hop and the NBA. if all the minorities left WWE like the Usos, Big E, and etc., I guess WWE fans would mindlessly watch WWE just like they always do.
Wrestling fans would not give a flying fuck, even if Dwayne Johnson went to TNA and talked trash about Vince cuz of it. Sure the "urban" market might switch but the white fans cheering for Cena, the Wyatts, Cesaro, Dolph, and the Shield are gonna stay with the WWE product til they're done watching wrestling completely.
Wrestling fans are too complacent with one product as it is in America, and its not mainstream enough like Broddie said, to be that much of a difference,
On the other hand, in this day in age of multiracialism and TMZ ethering lives, I could see it driving the business down to the dark ages if wrestling becomes entertainment seen only by racists with a racist st its head. It would make it even less mainstream than it is today.