Mudd was a crook and I hope that he would be viewed as this in any kind of society.
Trek never implied that there will be no power-hungry or greedy people anymore, it just showed a society in which this was not socially acceptable behaviour.
Your last paragraph shows what this is about, Puritanism, feeling guilty because you have not worked hard enough. If you feel guilty you have ample opportunities in the world of Trek to sustain this replicator paradise. You could e.g. enlist in Starfleet and take the night shift in engineering to exorcise your guilt feelings.
This is a serious point. Calvinism is about the paradox of freedom, predestination made people work like crazy, realize their fate so to say. And this lunatic stuff became the basic ideology of capitalism (back in the days). I have no idea how anybody could claim that the idea that people work to "better themselves and the rest of humanity" is more crazy than this.
and of course we have tons of people now, who are financially secure who continue to work. Athletes, movie stars, successful CEOs, those who've inherited money, etc. Obviously, they get satisfaction, not from the MONEY, but about something from the job-authority, a sense of doing good, the socializing, because they have fun, because it lets them be creative, etc.
Again, the question: why would this be any different in the future? It would just be everyone in society in this position, rather than a few.