Again, you seem to be confused. Microsoft isn't limited to what it can acquire because Sony is limited.
Just because Sony hasn't bought a company as big as ABK doesn't mean MS can't.
Sony bought big publishers years ago. They have purchased the vast amount of their game studios, just like MS have. Infact, Sony only has two more studios they built from the ground up than MS has (6-4).
Sony doesn't dictate the rules of how game companies can be ran, or how they can grow.
It doesn't matter if Sony fans think MS buying a big publisher isn't "fair". It doesn't matter that Sony doesn't have the ability to match MSs wallet.
And let's be honest here, of Sony could afford to buy ABK, and they had the opportunity, do you honestly think they wouldn't? You do realize the same Sony who doesn't do that sort of thing offered about 40-50 billion for Fox yeah?
Don't kid yourself. And, if Sony did buy ABK, the same people here saying how bad it is that MS is doing it, would all suddenly be touching themselves in their dirty spots about it.
Hey, it sucks when things don't go your way. It sucked as an xbox gamer when Sony was getting all the exclusive content and Xbox didn't. But you didn't mind then, so now that Xbox is getting exclusive content that PS isn't, you again shouldn't mind.
In the words of my PS friends, want to play the exclusives? Buy an xbox.