Ya'll need to stop with this whole 'We are the MOST desired men' narrative.
They see us as sexual creatures, and we pique their interest momentarily.
But if you asked the majority of Asian/White/Hispanic to describe their 'Dream Man', he would likely share the facial features of a white guy.
But to answer the OP's question-
1.) The pretty white girls who typically dated athlete's/ and rich black men would just affix themselves to successful white men.
2.) The Black community would probably improve
3.) Grotesque, obese, white women lose their traditional safety valve.
The only clear loser in OP's scenario is grotesque, obese, white women.