Because all races of women(including black women) are after the same prize. Access to his wealth. That's kinda the point. The athletes wanna deal with the one's who will give them the least amount of headaches, during the come up. They wanna deal with the women who are going to help him along financially during the come up. That's part of making the come up a little easier. If its clear both races of women are scheming (which is ABUDANTLY CLEAR), might as well enjoy the one who will give you the least amount of friction. And even then, that doesn't mean the white women are guaranteed the long term contract. Russell Wilson is the clearest example of having the ride or die White chick handle all the stress of the come up with him, just so he can leave her and end up with Ciara, who caught Russell during the glory chapters of his story. Russ ex probably did all the white girl handmaiden shyt for him throughout college and the pros, and yet the Black woman profited in the end. This is why black women love their relationship so much. But this rare.
But either way, like I said earlier, because of historic racial dynamics, its always implied that the white WAGs and HS Sweethearts are only with these brothers for the money. As if Black women aren't in it for the same goals. It's just that, because the Black community is starved for representation of wealthy black love, that Black WAGs get instant veneration and visibility more than non-black WAG do for dating the same black athletes. White WAGs don't become famous. There is no white equivalent to basketball wives. There is no White Ayeisha Curry, getting cooking shows being on morning talk shows. There are no white Savannah James equivalents with podcasts launches. There aren't white women venerated for playing the game like a Lori Harvey, who's praised for her hypergamy when it comes to rotating wealthy black male spouses. White women just scheme and be in the background and stay quiet.