I've always wondered this too. I've seen polls on this subject in the past and I'm always suprised there are that many people making over 100K. It certainly is possible, but I'm sure part of it is bravado or misrepresentation.
Most people have to work their asses off to earn that much, and like you say putting in 100-110 hours a week, if it works for you from a lifestyle standpoint, is your choice.
I'm in operations and it's taken me a number of promotions and hard work, being on call 24/7, working nights, weekends, whatever it takes to get me where I am today. I do better than average financially I'd say, and with incentives can make over 100K which I am happy with. From a lifestyle standpoint I wouldn't want to work 100-110 hours per week because it just wouldn't make me happy.
I still have a 10 year plan or so to save, save, save and then get the hell out of corporate America which is unfulfilling to me. I know some people love it and it is a sign of success and prestige. Unfortunately how much you earn in this country is often equivalent to how successful you are, and even how good a person you are. I'd still rather be a poor, but happy student or artist, than a rich, sad, corrupt businessman.