Given that the world at large still do not use linear workflow due to the non-pro Poser versions available, it would stand to reason that vendors would not bother mentioning Gc at all.  Maybe Pro users are in the minority; we technically know how to use it and how to change material node settings to achieve better renders.  But I'm just generalizing, of course.  I have seen some users, owning any pro series Poser, refuse to set any gamma just because it made unacceptable chances to their routine.

The problem with spoon feeding settings is that they can be misinterpreted as definitive settings for all lighting conditions, which they are not.  Frequent users have their own routines, but newbies have not developed enough experience to recognize what will or will not work for them.  Even mentioning Gc to a frustrated user would be enough to discourage any endeavor into 3D art.

But, again, are Poser Pro users in the minority?