MS could step in the game and say:
"Hi Activision, we heard you are thinking about dropping Sony? Well if you do so: here are 200 million USD... *alluring smile*"
Activision: "Oh MS, you are one nasty guy. But this is too much to say no!"
MS: "Come here and kiss me Darling!"
Activision: "Let's make some children [new IPs]!"
Imagine not having GamePass on your console...