George Chen, Alejandro Posada, and Leslie Chan have published "Vertical Integration in Academic Publishing: Implications for Knowledge Inequality".
Here's an excerpt:
This paper attempts to illustrate the implications of a simultaneous redirection of the big publishers' business strategy towards open access business models and the acquisition of scholarly infrastructure utilizing the conceptual framework of rent-seeking theory. To document such a transformation, we utilized financial databases to analyze the mergers and acquisitions of the top publicly traded academic publishers. We then performed a service analysis to situate the acquisitions of publishers within the knowledge and education life-cycles, illustrating what we term to be their vertical integration within their respective expansion target life-cycles.