You are going through a very difficult time right now, just struggling to survive. It takes a lot of guts to share something so personal.  And it is very disheartening to hear that the renders that took so long,  and were so much effort for you were not allowed in the contest. That trademark usage is always complicated especially when it come to artwork, and when it is commercial artwork (as all contest entries would be classified)  its even more strict usage rules. So the only option is to recognize and avoid those usage issues. Photograph snapshots are different,  because they would be personal use which is more flexible. It is unfortunate that is the way it is,  but if the  legal rules that exist in America, and  Renderosity has to adhere to them.

So you asked,  who is making money with DazStudio?  That is a good question.  Most users are just hobbiest,  doing it for fun and leisure past time. So there is no expectation of a return on investment.  If STEAM is any indication,  there is a collection of Daz users that make Visual Novels of the adult variety,  and some of them may make money, depending on how large an audience they manage to generate with the stories they provide.  Some user have used DazStudio for comicbook and graphic novel creation,  and again the amount of return on investment  is dependent on their ability to tell a good story and develop a following and audience. The challenge is these story driven options need literally hundreds of renders to create the content. Other setup tutorials sites and generate traffic and affiliate links.

Other Daz User become vendors  and sell their content creations to other users.  Everything from characters to clothing,  to environments,  to poses.  I had a look at your gallery.  You have a horse driving a car.  That is a fricken awesome example of posing ability.  I would suggest you try to make a pose set  for either G8F or G8M or G9MF and submit it to Renderosity for consideration. If you make some money you can do it again and again.    But it is important to realize, that the marketplaces at both Daz3D and here are not what they once were.  AI gen has really shook the market demand for 3D content. 

https://www.renderosity.com/brokering-with-renderosity