Earlier quoted context omitted.
They all got beaten because Apple and google thrashed them in all the ways that mattered.
Actually Windows Phone was pretty much killed by Microsoft's lack of marketing, developer incentives and general incompetence, the OSes (7 and 8 mainly, 10 was weird) were incredibly smooth, fast and well designed. For a short while (in between most popular apps gaining WP support and then dropping it) it was IMO the best mobile experience available. You could get a dirt-cheap low-end phone like the Lumia 520 and it…
The Metro/Modern/Whatever UI looked good in screen shots. In actual use the tiles just ate up a lot of screen real estate and rarely refreshed their content when expected. The UI inside apps was equally brain dead with touch elements often lacking borders. So you'd have to hope you aimed your finger perfectly on an icon. Because the UI could become unresponsive for unexpected reasons, especially on garbage phones, even if you hit an element it wasn't clear if the app was actually responding.
Windows Phone 8 and up was a dumpster fire. The highest end phones were just okay and didn't really hold a candle to the Apple and Android flagships of the time.