I think it's probably the same as for any line of business. You try and you might be successful first shot at it, but chances are bigger you'll fail at least the first time at it. Perhaps fail the second try and the third also and so on. How determined are you to try and try again?
I believe being successful out of the gate, lots have to fall in the right direction. For the few stories we hear of a studio founder selling off and be financially independent in one go, there will be many more stories we never hear about with misses and failures.