Well, it's because in Eastern Europe being amazingly beautiful gives you nothing. There are a lot of girls like that, standards are way higher and even if you're the most beautiful of them your perspectives aren't that much better. I suppose that in England or many other western european countries a chick that looks great might become a model and has hundreds of guys just waiting to get in her pants simply because it's something more rare, and because the culture is different - it ephasizes the looks. In Eastern Europe beatiful + stupid = a whore. And the best way to be a whore is to make porn movies. It means that the chick is not entirely stupid, since porn is always better than catching cold and/or hiv on the streets of nowhere.
At least that's how it works in Ukraine, Belarus, Russia etc. Technically we're in between the west and east, but our culture is far from being sex-centered. We don't even have a porn industry. Most "attractive girls" that are stupid end up with jocks doing low-paid work or move abroad (at least that's what they used to do). People here would despise girls doing porn or becoming nude models. Smart and attractive chicks are doing casual work, and looks don't seem to matter much.