One big reason Windows tablets and smartphones don't sell well is the app gap: There are far fewer apps available for Windows tablets and Windows Phone devices than for iOS and Android. With Microsoft's announcement of universal apps that run on all Windows devices, though, that may well change.
At today's Build Conference, Microsoft said that developers will be able to write a Windows app, and have that same app run on PCs, tablets, and smartphones. Developers will be able to customize the app for each device, but the bulk of the code will be the same for every device. On Windows Phone, the apps can run with Windows RunTime.
Developers will be able to use Visual Studio for all this, which will include a variety of diagnostic tools that will allow developers to see if a problem is occuring in their apps on all Windows platforms, and if so, fix them all with a single fix.
In addition, developers will be able to sell their apps so that they can be used across multiple platforms for a single price. So even if the Windows Phone version is sold, users could also use it for that same price on Windows tablets. Developers will also have the option of selling the apps separately.
Closing the app gap may be the most important thing Microsoft can do to help Windows Phone and Windows tablets succeed. The gap is very big, and very real. The numbers tell the tale. Apple said back in October that 1 million iOS apps were available, and AppShopper says that there are now nearly 1.1 million iOS apps. As for Android, AppBrain says there are currently nearly 1.2 million Android apps available.
That far outstrips what's available for Windows Phone, and for Metro. MetroScanner says there are currently just under 153,000 Metro apps available for Windows 8. As for Windows Phone, back in December Windows Phone Store finally crossed 200,000 apps threshhold.
Microsoft's new tools should help juice up that number, in theory anyway. Will it really be that easy to deploy the same app across multiple Windows platforms, or will it require a good deal of hand tooling and customization? There's no way to know yet. But if it's as easy as Microsoft promises, expect the number of Windows and Windows Phone apps to leap. And with it could come bigger sales of Windows-based mobile devices.