Windows CE never had the efficiency of scale convergence quite in mind, though. Windows CE was never quite Windows at the kernel level, for instance, and it was a competing OS inside Microsoft in some ways that mattered in the old xkcd siloes pointing guns at each other fashion.
Windows 10 mobile, especially towards the end (Redstone 3) was so very similar to Desktop Windows under the hood. It was still a fork, but it was a converging fork.
(UWP still sometimes gets unfavorably compared to the .NET CF, but UWP has always been more powerful and capable than CF and CE-era C++/MFC, even at its "worst" when Windows 8 launched. Especially now that .NET Core is open source and "leading" the .NET Framework/.NET standards rather than vice versa, UWP is much stronger than .NET CF ever was.)
But today MS has Xamarin that is a good enough cross platform framework for enterprise style apps.