The gloomy outlook for Microsoft's mobile platform comes in IDC's 2015 worldwide quarterly mobile phone tracker, where the analyst forecasts that Windows Phone shipments will have declined by 10.2 percent over the year to 31.3 million units, leaving Microsoft with 2.2 percent share of 1.4 billion units shipped.
IDC predicts Windows Phone will remain on the margins for the next four years, despite growth accelerating in 2019 when Windows Phone is expected to have a 2.3 percent share.
Windows Phone's decline over the past year will come despite Microsoft's devices having a lower average selling price (ASP) than their Android equivalents.
The lower ASP helped keep sales afloat last year but has done little for the company in 2015. IDC estimates that the Windows Phone ASP of $148 was $71 lower than the $219 ASP for Android devices.
So, what's to blame for Windows Phone low market share?
"The weak results can largely be attributed to the lack of OEM partner support," IDC noted, and Windows 10 isn't expected to help either.
"Despite all the effort Microsoft has put into the launch of Windows 10, IDC does not expect Microsoft's share of the smartphone OS market to grow much over the coming years," IDC said.
The state of Windows Phone today is vastly different to the outlook Microsoft gave when it acquired Nokia's handset business.
Back then, IDC predicted that by 2017 Windows Phone would have a 10 percent share of shipments, up from 3.9 percent in 2013. Microsoft was even more bullish, claiming that by 2018 it would have 15 percent share of 1.7 billion units shipped worldwide.
Besides a few bright spots in Europe, there hasn't been any sign that Windows Phone would live up Microsoft's expectations.
Incidentally, when Microsoft acquired Nokia, the Windows Phone share of 3.9 percent trumped BlackBerry's 2.7 percent.
IDC forecasts worldwide smartphone shipments to grow 9.8 percent in 2015, its first year on record of single-digit growth for the category. It also expects slow growth to intensify due largely to lower shipment forecasts for Windows Phone and for any OS that isn't Android or iOS.
IDC expects iOS shipments to have grown 17.3 percent in 2015 on the back of 226 million units shipped, leaving it with a 15.8 percent share, while Android grows at 9.5 percent to 1.16 billion units shipped, giving it a dominant 81.2 percent share.
The analyst expects the core Android platform to continue proliferating, thanks to companies like Xiaomi and Cyanogen.