The Xbox has always been a vehicle for the DirectX API. That is where it gets its name. By making a console that use the API, they convinced game makers to support it exclusively boosting both the Xbox and Windows. But the time has come that DirectX is fully emulatable on other operating systems, and falling out of favor compared to other options like Vulkan. Microsoft to their credit saw the writing on the wall way back with the Xbox One, where they strongly pushed streaming and other media consumption (or they thought they could just sell DirectX licenses to the other consoles and step away from the console market quietly). It turns out for once in the company's life it was thinking too far ahead. Streaming wasn't ready, it kinda sucked to use, and it lost a lot of favor with gamers.

So now they tip their hats and they're ready to walk away, hands completely empty.

Oh yeah except for all the money they got by juicing their stock price through purchasing indie companies and then firing everyone that worked there. It wouldn't be Microsoft if they didn't destroy the entire industry as they leave.