The new Microsoft is nearly unrecognizable. Years ago, when Windows was dominant and the smartphone era had yet to arrive, Microsoft was often the epitome of all that is wrong with a powerful company: They were accused of monopolistic tendencies, their arrogance made them miss the mobile era, and they stagnated for years while coasting on their most lucrative products.

But Microsoft is now born again, adaptive, forward-looking, and with products like its augmented reality HoloLens, occasionally almost cool. So when it was recently announced that Microsoft is entering into a deal to make its Cortana voice assistant work with Amazon's Alexa, barely an eye was batted. Once famously closed off, Microsoft now tries to be as open as possible, putting Office on the iPad, its Outlook email app on iPhones and Androids, and making its storage and note-taking services, OneDrive and OneNote, available on basically everything. Coupled with a growing cloud business, record highs for its stock, and still-growing revenues and profits, you might think things were on the up and up for the Redmond giant.

But the deal with Amazon is actually far less positive than it might appear. In fact, it comes from a position of weakness. As analyst Jan Dawson points out, both Amazon and Microsoft's voice assistants are dwarfed in usage by Google and Apple because those companies have their own massive smartphone platforms that literally put their assistants in people's hands. For Microsoft in particular, this deal is an attempt to make up for the fact that, without a real smartphone base of its own, its assistant is limited to Windows PCs — a category that is diminishing in importance. And that simple fact signals a bigger trend at Microsoft: that while the company may continue to survive and even thrive, once-unassailable Windows is likely doomed.

After all, the world has now shifted to mobile. As Microsoft itself has admitted, Windows barely occupies a fraction of all computing devices worldwide once you count the smartphones and tablets that have come to dominate not just individuals' day-to-day lives, but also the attention of developers and partners who wish to build apps and services on top of them.

It is true that Microsoft did try and build its own smartphone platform in Windows Phone and then Windows 10 Mobile. But those efforts were spectacular failures. Despite a forward-looking, digital-first design and interesting ideas like "live tiles" on the homescreen that rotated through updated information, any idea of Windows Mobile was hampered by a series of restarts, poor execution, and a corporate culture that simply couldn't allow mobile innovation to happen. Hardware was lacking, apps were missing, and consumer interest never built to anything approaching a critical mass. Even an acquisition of Nokia, the only real friend to the platform and a brand with enormous loyalty, couldn't save Windows Phone.

But even though Microsoft continues to thrive, that mobile mistake may in the long term prove to have been a fatal blow to Windows. In theory, Microsoft's aim with Windows 10 was to leverage its existing position to make up for its mobile failures. By unifying its various platforms under one Windows 10 umbrella, the idea was that an app developer could write an app for a smartphone or a PC and then easily port it from one to the other, thereby sparking interest in the platform. Trouble is, with barely any mobile users — and honestly, who could blame someone for not wanting a Windows phone? — there was no such uptake. Desktop users kept on using the traditional Windows apps they always have — Office, Spotify, iTunes, and tens of thousands more — while the Windows app store remained mostly barren. Windows Mobile remained insignificant.

It's developer interest that is key, however. Platforms only thrive when people are building things atop them. It creates inertia and a series of knock-on effects. Apple's massive success with the iPhone led to both the iPad and the reinvigoration of its Mac sales. Developers often create for iOS first, which means that the services that came to dominate the digital world — Facebook, Twitter, Instagram, etc. — are better on those platforms, which creates a virtuous circle for Apple. But it also means that in the future, new innovations — augmented reality, artificial intelligence, or the rise of new computing platforms like the productive tablet — are likely to also be found in the complete ecosystems of iOS and Android, rather than on Windows.

As such, the continually rising tides of Apple and Google's platforms will likely wash Windows away as people shift their work and play habits to opposing platforms. While many are fond of saying that you still need Windows for real work, as analyst Benedict Evans likes to point out, "the connective tissue of work needs to be rebuilt" in light of mobile, AI, and the cloud — and it's hard to see how Windows will be a part of that as new technologies emerge in new places.

It's not that Microsoft is oblivious to this reality. Recognizing a do-or-die scenario, Microsoft has now retrenched when it comes to Windows, putting its efforts into desktop and making Windows work on ARM, the type of chips found in iPhones and Android phones. The new, rumored goal is that using ARM will not only let Microsoft and its partners make thin, light laptops and tablets with great battery life, it will also let them create a phone that runs full Windows and can be used as a complete computer when docked into a keyboard, mouse, and monitor — and in doing so, give Microsoft a complete device to offer its millions of customers.

But this is likely just fantasy. As the deal with Amazon suggests, companies need a platform of their own to build out the vertically integration that has made Apple and Google so wildly successful. Platforms are like networks, and without the core node of mobile in a mobile-first world, Microsoft's Windows cannot last. The network effects common with platforms will occur, and momentum and interest will continue to rally around Apple and Google, and Windows will increasingly seem less and less relevant — like Palm, BlackBerry, and many more before.

To be clear, with its emphasis on the cloud, artificial intelligence, and more, Microsoft may well continue to thrive. But Windows — once the core of the company and seemingly central to so many of our lives — is likely beyond saving.