Its up to the individual, it is not fair to blame it all to the industry. I did get paid and would not work for nothing. I am still renewed and qualified to teach but I wont teach for fun, even I love diving. Weak link here is not the industry but non professional professionals.
I have worked in following schemes:
- Base salary + commission on courses conducted per student (harder the course higher rate per head) or extras (like night dive)
- Base salary + commission on sales, equipment and upgrade course, divemasters could score here well
- Base salary only, fixed rate whole month regardless how much business
As you see, I don't have "no salary" scheme

. You should be aware you are undermining others and the industry if you are not getting paid. I personally looked for a good diving center with long term employees. They are the ones who will care for their customers and instructors. In most of the cases I had social securities paid, in one case got paid holidays including flights home and back.
When I started my pro journey, I had just finished my studies in Finland, I wanted to get out of dark and cold for a while. My idea was actually to work perhaps 6-8 months somewhere warm. At that time, I did not worry too much on the earnings but I focused on getting a good company to work for. After working a while I have seen that actually I could put same amount on the side as if I worked in Europe. So I continued working and it was very hard to get me out of diving career after that. It was series of coincidences that I got back to a "normal" life and job.
If I look back, there are quite a few colleagues I know are still in the industry. My estimation is 60% of them returned back to normal life after 5-15 years of diving career. Some of them opened world class dive centres that are rated top by dive magazines, one of them has become the director of the dive center he (and I) worked for and is still working there..
So, it is possible to make a career, it is all up to the individual qualities and attitude, you have to play right. First step is to respect your self and demand remuneration for your labour.