What does it take to rely wholely on an income from a career as a musician?

You need to learn about the business end of the music business and not just the performance angle, and work on marketing yourself (or your band) as a brand. You also have to be willing to take what kind of gigs are available, even if it's playing at a party or in a small club. I've found that giving private lessons is another good way to supplement your income as a musician.

Talent and courage. My brother has been a professional musician as a primary career for 30 years. He doesn't have another job where music is his sideline or weekend job; being a musician is his job. While you can't count on a specific number of gigs each week as regular income, there are always peak seasons such as Holiday parties and in our city, Kentucky Derby parties, where you'll get more work some weeks than during other times of the year. It's tough being a musician, though, when you go to try to take out a loan or get health insurance. Look for an article by me about that soon. In the interim, see my article about the lack of respect full-time musicians receive at http://hubpages.com/hub/Give-musicians-a-little-re

well the number one thing the public demands of musician is that he be dead.

Moneywise? It depends how well you want to live. If you're making over 30,000 dollars a year, I would say that it's enough to live. You won't be a rockstar, but you'll also be saving yourself from the health-hassles of stress-induced illness. It's up to you.

Source:

I run http://JerseyMic.com, a website about open mics. I see lots of people trying to make it into a living.