Folks struggling to make it as indies should probably read this: https://klangmag.co/lifers-dayjobbers-and-the-independently-wealthy-a-letter-to-a-former-student/
Also he only mentions rich kids and day jobbers, but there's also "has a spouse with a good job", "their parent died and left them just enough to get ahead" and "managed to pay off house so don't have rent"