Why doesn’t Microsoft buy Unity Game development ?

Microsoft Windows 10 is supposed to be about Creators and AR Environments development, but it lacks tools for the development of 3D Games and AR environments. The 3D Builder tool is a pitiful tool for 3D modelling, and the 3D Assset store is worse than the Windows Store.

Many Indies use the Unity Game development, including VR, which is where Microsoft is supposed to be interested in. So why doens’t Mictosoft invest if good 3D Game/ AR development tools, or simply buy out Unity, along with access to its vast 3D Asset Store ? It is cross platform and well estblished. If Microsoft is serious about 3D it needs to up its game in developer tools big time.