My understanding is that the realistic way a musician makes a living without "making it" is session recording and teaching. What's the equivalent of that for comics?
The general rule of thumb here is that you can make a comfortable living with ~15,000 twitter followers - just enough fans to make a tour viable.
In that vein, being a session musician is also "making it" as well. But "it" is subjective - if "it" is being on stage, you didn't "make it" in either case.
Edit: Oops. Wrong "comics".