The odds of being able to make 300k a year at all, never mind without working 60 hrs a week, that it's not even worth discussing. Even the people on this forum are going to be in the minority if not extreme minority of people bringing in that kind of cash for less than 60 hrs.

That said, of course you don't need to spend your whole paycheck, but for the vast majority of people, I think you would have to spend so little that you'd really be sacrificing too much.