One thing I muse over sometimes in the context of billionaires is that, by and large, we should expect them to be strange and often unhappy people - simply because anyone more normal and well-adjusted would have stopped at, say, $10 million and $10 million typically doesn't accidentally turn into billions.

I think this is unlikely to be the case (that "well-adjusted" people would stop at $10 million), because the processes that lead you to earn $10 million, i.e. being the CEO of a major corporation, aren't things you just quit doing because you felt like "switching to consumption." Also, the type of person who is ambitious and self-driven enough to earn $10 million is likely to be someone who enjoys the process of their work more than consumption anyway.

I don't expect I'll ever earn $10 million, so that is a moot point, but if it happened you could earn millions of dollars working as a nurse, I wouldn't quit nursing just because all my "needs" were met. A lot of my needs (emotional, self-worth, social life) are met at work. Maybe an "inability to stop working" is an adequate description–but how is that unhealthy compared to, say, an inability to stop watching sci-fi movies? If your job provides a significant part of the meaning in your life, it wouldn't make sense to quit it and live a life of luxury. And high earning jobs (like being a CEO), although stressful, are probably much more "meaningful" than sitting in an office all day, at least to the type of people who are likely to succeed in those jobs.