These kinds of businesses don't seem to get much attention.
We've been a going concern for 4 years now, so there's still time for things to go off the rails; but for the moment we're killing our competition and there's essentially zero internal strife.
To keep the caps we're starting to divide like a bacterium - fostering other companies around our model instead of growing ourselves. We'll see how that goes. It's a little alarming to realize that we're creating our own competition, but there's precedent for it going well (e.g. Anchor Brewing in San Francisco).
It's a great way to make money, and I spend all the other productive hours of my week on my efforts to change the world. There's lots of blue-ocean ways to do that when the need to monetize takes a back seat.
Edit: I'm trying something similar.
I find the idea of working similar hours as you but still being able to provide for my family while spending a lot of time with them incredibly appealing.
Whereas at the moment, during the week I'm lucky to get more than 2 hours a day, the commute and workday eating up the balance.