Agree to an extend here, DE. Agree for the fact that the goodwill that MS cultivated with the 360 was killed outright by the Xbox One (Price, Kinect, NoDRM). Losing that momentum heading into the PS4/Xbox One era was devastating, but Sony was still on the up and up in terms of the PS3. Sony still had quite a few first party studios under them during that generation and even though the 360 was a strong competitor for the PS3, Sony still dominated on the exclusives, 3rd party timed-exclusives, and even having a lock on import-exclusives.
Going into the PS4 era, Sony ramped this up tenfold. It's much easier for the market leader to attain timed-exclusives due to there being less risk for the developers. Sony did it right and practically starved the Xbox One out of day of games. Taking a look at popular games like CoD, not only did Sony have marketing rights they used their position to get in-game exclusives in terms of content in games that didn't just end at CoD. Exclusives perks, modes, and characters in 3rd party games.
Now, if you're Microsoft, what do you do to stop the bleeding? Well, you're a 2 trillion dollar company for one. Your money alone isn't enough to secure 3rd party timed exclusives and you're not looking for a "quick fix" like that, so you start taking studios off the board. Onsies and twosies if you can do it, but if you can score publishers that are willing to sell and you're willing to pay then you use your strengths. In the PS1 days, Sony bought their first publisher and turned them into an exclusive/multiplat machine and it vaulted them into the front even before Microsoft game along with the Xbox.