My totally unrigorous theory: you don't have to be obsessive to be a reasonably successful employee, but you probably do in order to have a $1b exit. Those people then set the culture, because a bunch of the next wave of ambitious 20 year olds now want a $1b exit just like them. Some people say this is a bad thing, but what can you do about it? Culturally devalue money/success? How?

People don't like impersonal explanations, but I haven't seen a theory on this subject that includes in its model the cultural residue trickling down from the ultimate ability of 23 year olds in our industry to become insanely rich.