Not only is Sci-Hub pirating STM articles; it also has built a large collection of unauthorized university press monographs. This undermines the argument that Sci-Hub is an activist site fighting against corporate greed, as the university press community typically operates at a deficit. But university presses have many other challenges, and the threat posed by Sci-Hub is not the largest among them.
The sheer number of new marketing programs for books makes it hard to determine just how much a book costs. This post details all the factors involved with pricing.