Corporate and organizational mergers have been around as long as there have been companies. They have been a mainstay of my career in publishing, back to the early Nineties. The recent news about the proposed merger of Cengage and McGraw-Hill Education reminded me of their upsides and downsides.
On the plus side, they give the new entity greater market strength and position. They allow for greater distribution and dissemination of their content mostly internationally. Innovations in the separate companies are now available to the other company; potentially benefiting customers and authors. Financing for big initiatives is usually more common; allowing for innovation. These are some of the upsides, but they all come with the caveat these only occur sometimes. Of course, there are other benefits, particular to that merger.
On the minus side, right off the bat usually comes layoffs particularly in the service or support areas (HR, accounting, etc.). The merged companies may have too many products or many times competing products. This usually leads to products shedding, with some beloved titles being put out-of-print or sold off. Larger companies usually stifle competition among their smaller, remaining competitors. Larger companies are more difficult to nimbly react to market changes (think: steering a supertanker). Decisions become more distant from the day-to-day contacts for authors and customers. These (and others) are also particular to each circumstance.
As a whole, I am not a fan of these mergers primarily because of the trickle-down effect on customers and readers. They may experience some benefits, but as a whole customers are better served by smaller publishers and greater competition. The exact opposite of the way things are headed, but we all adjust.