It is NOT unusual for a first degree black belt to receive no pay. Style is irrelevant. It is also NOT unusual for first degree back belts to be taken advantage of by instructors, again, style irrelevant.
That being said.....I know some folks, from various, unrelated styles, who have opened dojos for various reasons.
1. They opened one because they loved Martial Arts so much they probably should have had their heads examined. They were full on Martial Junkies and God should have mercy on all of their/our poor souls.
2. They opened one because their organization wanted them to. It was expanding the Empire.
3. They opened one because they needed a place to train. Maybe their old place shut down - dojos go out of business as quickly as small eateries. Maybe their former instructor became too much to bear - for a multitude of reasons we read about on forums all the time.
I know a lot of people who began TEACHING for several reasons as well..........
1. They began teaching because they loved Martial Arts and went to every class they could. If you looked up as class started and they weren't there - you probably thought they were dead.
2. They began teaching because they got promoted through the ranks and all of a sudden - their Instructor wants them to teach a class. It's usually the kids or beginners. They're the most common "pass the buck" entities in all of Martial Arts. This usually coincides with the chief instructor getting out of shape, or getting into even lazier shape than he was previously.
If this happens to you and you still pay tuition and get no instruction - you should be buying bridges. I've accumulated a couple of very nice ones over the years and will gladly sell you one on the cheap.
2. People start teaching as a natural progression of dedication in Martial Arts, they begin as student with skills and abilities that have, and will have, profound positive effects on future generations for the remainder of all of their lives. Good examples of this are right here on this forum.
3. I think people sometimes start to teach because - sheet happens.
There's a lot I don't understand about life. At the head of that list is how somebody can love Martial Arts as much as they do - then allow themselves to let everything deteriorate. When you promote somebody to first degree Black Belt this should be a very big deal. And that person needs even more instruction, more understanding and more physical, balls to the wall training than they've ever had before.
They should also be cut some slack for getting to that rank point. If necessary, adjust the schedule so YOU can teach them more. Yes, it adjusts your schedule too, which can be a pain in the backside, but hey, you made the move to open a school. What, you think this opening a school thing was going to be easy? You think you now have some minions to serve at your beck and call? (Uh oh....I'm starting to rant.)
The flip side of this, the Yin Yang of it if you will, is this is exactly how I started teaching. By being taken advantage of by an unscrupulous, bounder of an instructor.....and it eventually turned out to be the best thing that ever happened to me.