A huge part of Microsoft's strategy for Windows 10 hinges on what it calls "Universal Windows Apps."
The sales pitch for consumers is simple: If you buy an app from the Windows Store, it'll work exactly the same way on your phone, tablet, computer, and eventually, the Xbox One video game console — because it's literally the same program on every platform.
Microsoft CEO Satya Nadella has highlighted Universal Windows Apps as a way out of the company's old-school lines of thinking that placed the PC at the center of the world. And he's vowed never to make that same mistake again.
Ultimately, Microsoft says it expects a billion active Windows 10 users, across the full spectrum of devices, within the next two or three years. Software developers wouldn't be able to resist building apps for such a huge market. For comparison, the Apple has sold about 700 million iPhones over an eight-year span.
There's just one big problem: Microsoft hasn't given developers any real reason to build Universal Windows Apps.
At least, not yet. And if they can't nail this, Windows will continue to fade into irrelevance.
Old PC apps work just fine
The first big problem is that old Windows apps work just fine on Windows PCs, so there's no reason for developers to rush to update them for Windows 10.
There are a few exceptions, like Twitter and Fitbit. Otherwise, the Windows Store is largely populated with the same group of apps, including a lot of half-baked misfits, as it was during the Windows 8 days.
To be fair, Windows 10 is still really new.
The first version, for users to upgrade their older PCs, just came out in July. Brand new PCs running Windows 10 are still scarce — the big wave is expected in the fall — and the enterprise (big business) and mobile versions of the software aren't here yet.
On the other hand, developers aren't exactly tripping over themselves to announce their support for Windows 10.
When I asked Slack, the hugely popular work chat app, if they planned a Windows 10 release, a spokesperson said only that the company was building a mobile app for Windows Phone 8.1 (the current, soon-to-be-replaced Microsoft mobile platform). That app will also work on the next Microsoft mobile platform, Windows 10 Mobile.
That's not a newfangled Universal App — it's just a regular mobile app that will run OK on Microsoft's next mobile platform, too.
In the meanwhile, Slack's existing Windows desktop app works on every version of Windows from 7 through 10, without Slack having to lift a finger.
It's a common sentiment. Thanks to Windows 10's support for legacy apps, it'll run any existing software without any changes to the code. And if it ain't broke, why fix it?
Nobody uses Windows on phones
The second problem is that very few people use Microsoft's mobile phones.
The big promise of Universal Apps is that developers who have built great Windows apps won't have to do much to get them to run on Microsoft's mobile platform.
But as mobile phones running Apple iOS and Google Android have conquered the world, many of the best and most innovative apps — think Snapchat, Instacart, Uber — were never designed to run on a computer at all. They rely on mainly-mobile features like location detection and the camera. They aren't, and never were, Windows apps.
As analyst Benedict Evans put it in a blog post: "You can't tempt developers to support Windows Phone by saying 'it's easy to deploy your desktop app to mobile' if there is no desktop app. So Windows is not a point of leverage for Microsoft in mobile."
From the other side, why would a developer who has created a great PC app spend any extra time creating an app that works on Microsoft's mobile platform?
Microsoft's mobile share is less than 3%, and the fact that the company has recently restructured its phone division and taken a massive write-off on its Nokia acquisition doesn't give developers a lot of hope that the company's going to make a big new push in mobile.
"Microsoft's recent de-emphasis on Windows phones has gutted the promise of Windows 10 Mobile, leaving the primary usefulness of Universal Applications — same app on desktop-laptop-tablet and phone -- in question," Directions on Microsoft analyst Rob Sanfilippo recently told InfoWorld.
Building real stuff for real PC users
Finally, as a developer, writing a Universal Windows App means giving up a certain degree of freedom, says Brad Wardell, CEO of Stardock, which has long been making games and productivity tools for Windows.
Microsoft limits the API platform to build Universal Windows Apps, Wardell says, such that every app runs in what programmers call a "sandbox," meaning that it can't "touch" other apps.
This is very similar to how smartphone apps are built, Wardell says, but it makes it a lot harder to build super-serious productivity apps. The mobile/desktop divide is important to understand, Wardell says.
"Apple understands that Mac OS is a different beast than iOS," Wardell says.
Take, for example, Adobe Photoshop. Adobe actually offers some extremely lightweight versions of its apps in the Windows Store, originally built for Windows 8.
But they're more of a novelty than anything: They don't support many of the features that hardcore Photoshop rely on. And thanks to Microsoft's sandboxed development model, you can't do things like download and install third-party filters and plug-ins for it, the same way you can for the legacy Windows version.
The same goes for Excel macros, or browser extensions, or anything else you download to really extend a product on a Windows PC.
In the end, you get a mobile app running on your desktop without all of the features you probably wanted in the first place, Wardell says.
"I want to build real stuff, and I can't build real stuff on that API," Wardell says.
Downward spiral
Microsoft wants a billion Windows 10 users.
The most recent estimates from Gartner predict that the world will buy 933 million PCs over the next three years — including desktops, laptops, and premium "ultramobile" computers (think super-thin, super-portable).
So even if Microsoft just continues to dominate the traditional PC market, and all those PC buyers happily keep running their old Windows apps on their new computers, Microsoft will get its billion users.
Many of those billion users will happily go on to pay Microsoft the subscription fees for Office 365, Groove music, Xbox Live, and other services that don't depend on owning a Windows PC.
Universal Apps are simply a last ditch Hail Mary effort to make Microsoft relevant in mobile. Why not just give up this fight and move on? In fact, one part of Microsoft seems to be implicitly acknowledging with its rush of apps for iOS and Android, including its Office suite.
But over the long run, it means that developers will gradually find less and less reason to build for Microsoft's platforms at all. As iOS and Android apps get better and better, and iOS and Android tablets become closer and closer to replacing PCs, Windows will continue to lose relevance.
