There are two kinds of people in this world:
1) Those who hit some ceiling and actually achieve contentment.
2) All-consuming psychopaths who love looking down on everyone else for their lack of ambition.
I was born the second, but I sure as hell don't have to stay that way.
Also, side comment: some of us don't want to be employer-capitalists. We like doing things for their own sakes, not so that we can turn every activity in life into a money pump. As such, by your notions, we simply don't have ambition.
By my notions, the default ambition you remark upon, the urge to become a wealthy, high-status leader of some sort, is indeed psychopathic. Why should I want to become a capitalist, military general, or statesman? I could stand being an activist leader, but I don't think I'd be much good at it.
On the other hand, if you ask me if I wanted to, for instance, destroy all existing social relations and have a socialist revolution, I happily say "yes". But somehow Revolution is simply not as ambitious as "become an employer", or as "become a research professor" (which is actually harder than becoming an employer).
Which, again, makes it sound to me like your definition of "ambition" is "a rise in wealth and social status" rather than any coherent notion of actual achievement.