Of course, the historians here are likely to tell me I'm out to lunch and I'll have to rethink my hypothesis.
I'll give you a couple of things I'm sure you already know about.
1. Perfumes
2. Deodorants
3. Cosmetics
4. PHERMONES
I can guarantee you that if a woman had hair on her back and howled, there'd be a long line to "service" her if she overproduced pheromones. Now they are covered up by assorted other "stinks".
And you add that the "preferred" ones now are so wrapped up in conquests and notches on their belts (both sexes) because of birth control and you get the ugly reproducing and happy and the "pretty" ones sterile and empty. Maybe we have a negative selection going on. I think having a really beautiful daughter or handsome son can be more a curse. My experience is that the really pretty people are so wrapped up in being looked at that they neglect their heads. Society has gotten in the way of Nature.
So the ugly ones sneak under the radar screen and pass on their genes. Many pretty ones end up old and flabby and alone.