This should be a major point in stratifying comics. There are the Seguras, D'Elias, Schaubs, Cummings, and Callens of the world whose major accomplishment was "hanging in there" and steadily padding their resumes thanks to huge stipends from their rich families.
Then there are the self-made comics who wind up fagging out for other reasons.
I'm dating a TV reporter and it's the same thing. Most journalists don't make enough to survive unless they're in a major market (or have a prime time in-studio gig which also favors tenure). So the ones who break through are the ones who can stick it out through the "pay your dues" years. The promotion system favors longevity, not achievement.
She told me a story about when she worked in a very very small, dusty midwestern city and there was some reporter whose family used to send a private plane to take her home on the weekends. She eventually wound up as an anchor in a top 10 market.