You are wrong unfortunately. Those other acquisitions were small or in areas MS didn't have their own operations built up.
MS doesn't need two of all the teams they now have two of.
I don't feel like Microsoft was centrally staffed to support all this growth. They leaned out gaming a lot under Windows and a publisher was always in play once they decided to re-commit to gaming. Going from 6 studios to 23 is a lot for any publisher to handle within 2 years time and if they didn't buy a publisher, expanding those operations would've made sense either way.
Also these things don't exist in a vacuum. With the way Zenimax had been trending lately, nobody would have been surprised if entire studios got shuttered. I think it's way too early to say if this is bad for employees of Zenimax. Going by Nadella statements regarding acquisitions in the past, I personally think people should wait before doom and glooming the employees that work there.