First of all i completely disagree, Look at Rosie O Donnel.. if you can:)
haha in all reality, if an attractive person is successful i would think its because with attraction, and beauty comes gifts and praise. Also a sense of Intimidation and self worth. If your told your attractive every day, and people hold doors open for you, buy you things, and you normally have a romantic person to lean on, life is just easier. Also as an attractive person your self esteem is always on the rise, if people are infatuated with you, they wont question you, they will let you have what you want with minimal effort.
I believe another reason is less attractive people are intimidated by the success and instead of confronting them, they step down and let them have success.
Might write a hub on this soon!:D