I'm well off and I work considerably less hard than many people making close to minimum wage. I'm treated better, trusted more, respected more, and have much more flexibility in my work.
Will and work ethic are weakly necessary for success, but they are not at all sufficient for it. (not successful) -> (not work ethic) is denying the antecedent: (successful) -> (work ethic) is, if not always true, at least often true, but that doesn't imply its converse.