Microsoft's ambitions are far grander than Sony or Nintendo. They're stocking up to compete against companies like Meta and Tencent who are trying to eat their way into the industry. Microsoft is preparing for that future by buying publishers so that they can have the advantage over any incoming player.
It's very different from Nintendo and Sony who are moreso investing in themselves rather than prepping for a subscription based metaverse future.
It's completely off topic but I disagree with this statement. I believe Sony and Nintendo will acquire publishers in the future, although in Sony's case, it will be in the near future.