The story goes way back when Apple’s iOS & Google’s Android took over the market rapidly & in such a manner that it made the Symbian OS non-existent, resulting in absence of Nokia from the cellular phone market for a while.
This was the same point when Windows decided to enter the cell phone segment. Microsoft brought innovation in the phone by enhancing user experiences, with Live tiles, social network integration, Hubs, Rooms, and the fluidity of the OS.
Windows OS based phone was way ahead of its time, offering detailed display & tile icons with live information on them, a calendar surfacing your next appointments, a messaging app presenting snippets of texts, a phone app with your last missed call, and so on in opposition to Apple’s static icons.
The OS was also an upgrade over the then popular Google’s Android, as Windows OS was comparatively faster than Android.
Windows also associated with brands like Samsung, HTC & Nokia & launched some premium phones which were welcomed by the audience.
If everything was likable..then why did the Windows Phone go extinct? Why don’t we see or hear of it now?
Windows Embedded Compact was incomplete & it limited Microsoft’s ability to bring the power and versatility of Windows to a mobile form factor.
The industry was moving at a fast pace & unfortunately, Microsoft couldn't catch up. Apple and Google had developed carrier, developer, customer and OEM (Android) relationships years before Windows Phone 7 arrived.
The App Gap - Compared to the wide range of free apps available to users on Android platforms, the Microsoft Store had very fewer apps
The absence of essential Third Party apps like Youtube further resulted in making the Windows OS based phones less engaging
So it was as if whatever Microsoft did to keep it's Windows OS alive was timed wrongly without understanding the psyche of the users at that point of time. It offered nothing as an improvisation over its competitors.