When they're no longer in the hardware space I can definitely see them buying more. But that all depends on how well the transition to full on publisher works out over the next few years.
As for them buying Sony or Nintendo. Literally zero chance of that happening.
Not just because of the Japanese government politely telling them to fuck off, but because that's too big of a risk, even for a juggernaut like MS. You're looking at around 200 billion Dollars for one.
Take 2 is possible though. Certainly not anytime soon, but in the future I can see them taking a punt at acquiring them.