Winning the "ovarian lottery" means you were born with advantages that you didn't earn. Someone born in the US, has a huge advantage over someone born in a 3rd world country. Luck probably plays a bigger role than hard work (in success) due to these non-earned advantages. Many successful people would rather believe that their hard work was the reason for the success than admit their good fortune.
For example: I don't doubt the the Winklevoss twins are hard workers [you don't get into the Olympics without hard work] but I think it would be reaching to ascribe their current station in life to just hard work.
Working hard is a necessary but not sufficient condition for success. Like Patrick said, working very hard at digging ditches is not going to land you in a C-suite, obviously, but very few people end up successful WITHOUT working hard.
For example: I don't doubt the the Winklevoss twins are hard workers [you don't get into the Olympics without hard work] but I think it would be reaching to ascribe their current station in life to just hard work.