I guess how they buy studios and what they do with them historically has something to do with it too?
Look at most acquisitions Sony has done: normally there is quite a long courtship where the companies work closer snd closer and then one or two bigger bets given to the second party dev which result in an acquisition of the company is willing and has passed these "fitness" tests.
Sony has historically given a lot of freedom to their Studios and buys studios they feel they can entrust and grow and their software output over the last 25+ years speaks for itself.
Also, they have been adding new teams and grown organically their existing studios which is kind of like buying or founding a new one, but sounds less fancy I guess.
I've read a interview from Molyneux once, on why bullfrog died after the acquisition from EA.
Long story short, they had a tiny building before the acquisition, where they had fun, played games and talked to each other about the games they wanted to make.
After ea acquired them they became huge with big buildings and got a very professional touch.
Problem was, they didn't act like best friends anymore. There were no time to play, and all the ideas seemed to have been drained out,which led to ea eventually shutting them down.
While this story is about bullfrog and ea, I doubt it's much different here with Microsoft, as I think it has something to do with the "American way" of doing this, where Sony, a Japanese company, might have a different opinion.
While weve seen coalition become a Gears studio, or playground games only become a racing studio, could be to prevent what happened to bullfrog. How worse it might sound, you can't kill the creativity if it isn't there to begin with, and then why not do what you're good at?
I don't know much about how Sony acquires other studios, but I think we're seeing the difference of how an American company handles stuff and then the Japanese, because Microsoft seems to be the common way where companies from there tends to do the same.