Its a rather sad and one-sided way of viewing things. I think the same psychology applies to men; when you can get something easy you don't value it as much. How many guys do you see chasing after nice homely marraigaeble girls? 
in the science of sex vids that I posted. When they had women and men of diff attractiveness (with numbers on their heads), they had to pick---if I remember correctly, many would overshoot (men and women), but then would realize and start shooting for their "corresponding attractiveness".
In the real world, this tends to happen for men and women, barring men who are rich.
Rarely do you see a man who is deemed very attractive by women with a homely woman. And if he is, it's either an ego thing for him, or she used to be attractive, and he's grown to love her over time. Example would be Pierce Brosnan and his wife.
Now, since women tend to be the ones in our society who do the picking, if a hot chick intentionally picks a homely looking nice guy, either he has money, or she knows that his ass won't leave as his chances of getting the same deal are slim. It's an ego thing for her, and security---he's more apt to stay than a attractive guy.
Looks get you in the door as a dude, personality is ok, but money is a must.
Put all three together, a unattractive "nice guy" has no chance against that.
And a dude who knows he's the shit, can act like it.
And, you can't hate on that.
