One other thing to consider is that working on your own games can still help advance you professionally even if they're not profitable. I haven't made enough money from my own apps and games to live on, but I think that portfolio has helped get me contract work that pays the bills, and what I learn from my own projects I can apply in work that I get paid to do (and I always learn tools and techniques in paid work that may be useful in my own projects, so it's all good).