Agreed, I was ambiguous on this point. It would be nice to make a living from it (of course!), but I've got other apps in my brain that need building, and other types of work that I do, so it's not necessary. I don't have all my eggs in this basket.
Let's say: in order to be more than a hobby, a program has to be financially self-sustaining. For some software, that can mean enough to spend 10 hours a week on it, and for other software, it might mean enough to hire a team of 50 people to work on it full-time. Below about 10 hours/week, though, and it starts to lose the ability to be called self-sustaining. There's just not enough hours to take on significant work.
> I found my only success with a unity plugin was to release it for cheap/free to build users and charge for new features at freelance rates.
This is a great and helpful data point.