At the same time I've had periods where I worked hard and was focused and passionate about what I was doing, and periods where I was not passionate, unmotivated by a crushingly poorly run organization and did not work very hard.
The periods where I was focused, passionate and working hard were the more successful ones, and successful enough to carry me thru the down times as well.
Luck may have put Michael Lewis at Goldman Sachs, but luck didn't determine his level of success. After all, his success comes from writing books, not being a goldman boy. Sure he wrote his first book about that period, but that book took a large amount of focus, passion and effort to create.
That said, I certainly find myself occasionally jealous of people who seemingly lucked into great success. If I'd never applied myself, and thus never had success myself, I'd probably think that luck was the actual determinant of success.
Edit to add: In this post I deliberately talked about my personal experiences. I didn't make a broad sweeping statement that luck doesn't determine success or failure for everybody. However, clearly people object to the political incorrectness of not supporting the ideology that argues "luck determines success, therefore the rich should be taxed to pay us! we just weren't lucky!" Note that I did not address that argument, I just talked about my experience. But because my experience is inconsistent with the distorted view of the world, it is "politically incorrect" and thus should be kept from the eyes of others, lest they be influenced, my post has been made visually unreadable. I find this anti-intellectualism distasteful.