This is a question that I have spent a lot of time thinking about lately. I work as a dialogue editor, and while it is great to have a Pro-Tools/audio job that's secure and 9-5 (ish), I spend my days editing clicks and pops out of VoiceOvers. Let's just say that it's not exactly thrilling. But it pays the bills...
But here's the thing, if you spend more than you make, you will always find yourself in financial trouble, even if you get to Hollywood level. I've been reading a lot of stuff by guys like The Minimalists and In Over Your Head about how to set up your life to better facilitate doing what you love. It's been very inspiring. The idea of paring down your life (and Stuff) so that the money you make becomes more than you actually need, whether you bring in $30,000 or $500,000. I won't say any more than that (for fear of becoming preachy), but it's entirely possible to be happy and fulfilled making $1500-$2000 a month.
It's a question of what you want. If you want the house and the family it's going to cost you a lot more money than living out of a studio or bedsit. If you want to be able to keep up with all of the new techie toys that get released every every six months you're going to have to find a way to make enough money to get all the stuff without drowning in debt, not an easy task.
But the first thing is to figure out what you want, then budget accordingly.
My dream is to become an itinerant troubadour sound guy. I want to travel the world with my MacBook Pro and PCM-D-50 and work with as many people on as many things as I possibly can. I'm about six months away from being able to set off. I'm in the process of selling all of my extraneous gear, computers, clothes, books, shoes, frying pans and kitchen gadgets, and trying to save up as much safety money as I can. I know for a fact that I sure as hell won't be making a ton of money, but I don't need money. I need people and work and happiness and fulfillment, which my current well-paying, VERY SAFE job simply isn't giving me.
Maybe it'll work, maybe it won't, but as I'm sure someone much smarter than me has already said:
Failure is success, after a fashion.