Xbox's acquisition of Activision has not gone without pushback, as both the FTC and European Commission have been putting the deal under scrutiny to determine whether or not it should be allowed. One of the countries that has taken part in this investigation is Brazil, as the country's representatives asked third-party publishers how they felt about the acquisition, and Sony's answers stood out.
Sony's response, as translated by VideoGameChronicle, highlights Call of Duty's immense popularity. "The importance of Call of Duty to entertainment, in general, is indescribable." The document continues to compare the franchise to some of the largest in entertainment, including Game of Thrones, Star Wars, Harry Potter, and Lord of the Rings.
Sony continues making drastic claims about the Call of Duty franchise as a whole, suggesting that "no other developer can devote the same level of resources and expertise in game development." It's clear that the company relies quite heavily on Call of Duty sales, especially since it is "overwhelmingly the best-selling game" in its genre. The document goes on to explain how the franchise sells tremendously well, even during its weaker years, with further comparisons about how Battlefield lacks the same popularity.
Sony believes "Call of Duty is so popular that it influences users’ choice of console, and its network of loyal users is so entrenched that even if a competitor had the budget to develop a similar product, it would not be able to rival it.” Further on, the document explains that "players would be unlikely to switch to alternative games, as they would lose that familiarity, those skills and even the friends they made playing the game."
While this doesn't explicitly state what Sony's fear is, there's a clear indication that Xbox's ownership of Call of Duty puts the company in a position to push exclusivity at some point. And if that happens, Sony will not be able to rival this first-person shooter goliath and it would eventually result in players swapping consoles.