Some thought in response to Elyse's post.This is what I get from Jackie: If you can support yourself entirely by doing art then great! do it! Just like Jackie herself, she lives off entirely from her art sales. But she also pointed out how other people choose other ways to balance between living their dreams and supporting themselves financially, just like her friend who do tax for a few months per year. It's not that one way is better or preferable than the other. Just whatever works for you and your situation.
I personally think that it's great if you can live your artistic life while make a living out of it. But I have no problem with an artist who spend some time doing other stuff to make a living. I don't think that would harm your art practice (unless you are a dancer or a music performer who probably cannot afford to go a few months without practicing)
A person may have lots of interests and maybe one passion in life. In my opinion, you certainly need to maintain a focus and set goals to fulfill your passion, but it doesn't mean you have to devote your entire life doing that one thing in order to excel in that field. I think people get a lot of experience and inspiration while experimenting and trying to a variety of different things. Especially with art, your artistic inspiration might very well come from your wide array of life experience. Who knows, maybe an experience with the up and down of the stock market might give someone an inspiration for a great work of art!!! :)