Honestly, Microsoft bought them because they thought it can magically catapult them to #1 in the gaming industry. And they have, in a sense. The advantage of having so much money that you can buy your way into the industry. But the problem is that Microsoft has no idea what to do next.
MS has been doing that for over 20 years, no news there. The reason for acquiring is to deny acquisition to others, and to ensure MS’s ecosystems have software, I imagine.