The least Desirable vs the Most Desirable Men and Women

I've been watching a video series recently that has me thinking alot about the dating game and marriage possibility.  I have wittnessed many women dating and marrying thier so-called "lowly black men" while their single black sisters, who are looking for love, are staying single while they wait in vain for a "good, black man" to come down the pipe. Why is this happening? Where did these black men go?