Because those who are considered a 9 or 10 out of 10 looks wise know this, and they cycle through men due to the mantra of "I can treat someone like absolute shit, and even if they tire of my shit, 10 men will clamor to be the replacement". Add in the fact that due to the constant attention they get from men, they are playing the world like playing a game on cheat codes. As those who are gamers know, it might be fun to do that for a bit, but then the game very rapidly gets boring. What happens when you get bored and you have nothing fulfilling to do? You seek out more and more extreme things for fulfillment - which usually turns to drug and alcohol addiction.