It is not only a question of being profitable, there is also a certain risk involved. It is ridiculously easy to produce profitable R-rated material. It is maybe not as profitable as a successful "family friendly" product, but if you know that you are mediocre you are better of producing cheap entertainment instead of high art.
I suspect the Renderosity PTB know this and act accordingly.

You know what is right for you. I know what is right for me.