Out of those, I think either selling games, or owning a location where you keep 100 percent of the coin drop will have you taking home the most, but even at that, it wont be much.

If you are serious about this, i would go to college and get an engineering degree in either electrical or mechanical engineering and then get a job working for Stern or the like. That will have you in the build process of machines, and have you around pinball all day everyday. I don't think it will get much better then that if pinball is truly your life.