Hm. I'm not convinced - there are plenty of professional programmers (who make maybe $60k, which is a good salary) working at Java shops who do 8am-5pm and think a monad is an itinerant who lives in the desert.
There are loads of professional teachers, professional medics, professional sanitation workers, etc. who just turn up, do the job and go home. Some may and do work long hours for little reward, but a lot don't. There is a culture in academia that you may, sometimes, when you really need to, you may take the weekend off. Or Sunday, at least.
You're right, I didn't choose my words well. I should have dropped "career" from the statement and just left "pursuit," something you do in a large part for its own sake. And maybe I should say "It's not brilliance that defines a good X," because clearly you can be a subpar artist/programmer/teacher/etc. and get by on some combination of luck, connections, politics, organizational apathy, and so on, but if you really want to be the best damn X you can be, it's going to involve a lot of elbow grease no matter what that X is.
A lot of people are in academia precisely because grinding out Java for 9 hours a day, or what have you, sounds like their own personal version of hell. The work can be all-consuming but if you're doing it right, it's fascinating. The intangible value of not being bored is something I see glossed over again and again by outsiders.
There are loads of professional teachers, professional medics, professional sanitation workers, etc. who just turn up, do the job and go home. Some may and do work long hours for little reward, but a lot don't. There is a culture in academia that you may, sometimes, when you really need to, you may take the weekend off. Or Sunday, at least.