I genuinely believe Michael Stern and Rushmore does this as a labor of love. I have yet to see a commercial except for the sale of a cook book or two. It ain’t like they are getting rich off the sale of some books.
If I were them, I would take it commercial. They have enough readers that are focused on just a few subjects.
I personally do not see how they can afford to do it like they do!
Paul E. Smith