Google was extremely aggressive in muscling Microsoft out. They refused to release a Gmail, YouTube or Maps client for Windows Phone but made sure those services did not work (properly).
And indeed on top of that, Microsoft switched UI frameworks 3 or 4 times. And they left phones behind on the old OS releases repeatedly, that then couldn't run the new frameworks.
Still, Windows Phone its UI concept was really great, and I sorely miss the durability of polycarbonate bodies versus the glass, metal and standard plastic bodies of today.