You mean Microsoft proactively kept shooting devs in the kneecaps?

Leaving phones behind on old incompatible OS versions 2 times in 3 years and switching app frameworks 3 times in 4 years does not a good app developer experience make.

Piled on top of that, Google became actively hostile to 3rd party developers building support for YouTube (and Gmail and Gmaps, but those had workarounds / alternatives).

What a colossal disaster. I was a huge Windows Phone fan, so their yearly missteps were quite painful to watch. I was especially annoyed when my first gen WP wasn't going to get an upgrade to WP8. My HTC 7 Pro is still my favourite phone I've ever owned, but after that I finally gave up and switched to Android.