With the announcement of 'bridges' to help Android and iOS developers compile their applications to native Windows 10 'universal' applications, many have questioned the future of Windows Phone as an OS. In a sense, they're right - Windows Phone as it exists now is about to cease to exist. But it will transition completely seamlessly (in theory) into the Windows 10 - at which point it will share a platform with the dominant desktop and laptop OS on the planet. And creating Windows 10 applications will see a dramatically bigger potential market - hey, I've done a handy graphic (below) to make the point!

As you'll see below, a picture really is worth a thousand words. 

Note that the exact definition of 'installed base' varies according to who you talk to, so I've used common sense, trying to estimate the number of devices/computers still in active use. So, for each platform:

• Any Windows laptop, desktop or tablet running Windows Vista SP2 or above (XP being no longer supported)
• Any Windows Phone running Windows Phone 8.1 or above
• Any Android smartphone or tablet running Android OS 4.2 or above
• Any iOS smartphone or tablet running iOS 7.x or 8.x
• Any Mac OS X laptop or desktop running Leopard or above

Note also that Symbian OS and Blackberry OS (various versions) have been omitted from the chart since the numbers are just too small. Both now significantly less than 50 million, so in the noise in terms of the scale here. Ditto Linux used by consumers, Chrome OS, and a myriad other 'Where are they?' options...!

Note also that I've (for the purposes of making a point!) assumed that every Windows desktop, laptop, tablet and phone user will have upgraded to 'Windows 10' by the end of 2015. Now, somewhat obviously, in the real world, getting everyone to click or tap on the 'upgrade' button will take longer than that - just think of all the 'mum and dad' computers, and indeed phones, which "work very well, thanks, so why should I change things?" And think of all the companies needing time to test and roll out.

But a significant majority - certainly all the active users, the people who do the browsing of application stores and buying, will have upgraded to 10 by the end of the year. Even on phones, I suspect, despite the best efforts of some networks around the world to hold things up with firmware approvals.

And don't get too hung up on the binary switch below - even those still on Windows 8.1 and Windows Phone 8.1 will still be part of the platform, essentially, so the total number stays the same, whatever colour the bar below is(!)

Leaving aside my caveat about 100% conversion to Windows 10 (though why wouldn't it get fairly close, since the upgrade is free?), the takeaway here is that right now a developer looking at creating an application for Windows Phone has a relatively small addressable market. We've seen various companies pull their official applications from the Windows Phone Store because they claim they haven't got the resources to support the application for a fairly small number of users. For example, taking the example of Chase and Bank of America, a USA-specific banking application might only have a few tens of thousands of active users, while a similar app for iOS or Android might have millions. Of course, Windows Phone is more popular in the rest of the world, so this hundredfold difference is unusual, but you can see some developers' point.

In contrast, when Windows 10 is out, across all form factors (so by the end of Autumn 2015), the bright blue bar above is larger than that for all iOS devices and very comparable with the green bar for Android, which suffers in that it only applies to phones and (to a small degree) to tablets. While Windows 10 offers a very real platform that spans desktop, laptop, tablet and smartphone.

For consumers, having the one platform across all form factors is good because it means that their phone interface looks the same as their desktop or laptop, familiar and with no unpleasant surprises. And being able to buy an application on the phone and then automatically have it installable on the desktop (for example) is a significant money saver. For companies, Windows Phone is already quite attractive, in terms of robustness and configurability - with Windows 10, the advantages of rolling out universal custom apps and the easier support will only make things more so. Admittedly companies will take a year or two to get 'there', but Windows 10 does seem to be the 'next Windows 7' in the business world.

In short, Windows on phones is currently limping along in terms of market share and acceptance, but it's about to become part of a much larger ecosystem. And, given that neither Android nor iOS scale past the tablet*, it's an ecosystem that should be the widest-ranging of them all.

Comments welcome, of course, plus we'll be discussing this in the next AAWP Insight podcast.

* You could argue that Google services across form factors and platforms, ditto iOS with its services and continuity utilities, mean that end users don't have to stick to one platform exclusively and that they can mix and match. Which is true, though a) given a choice, I think having just one platform would appeal to many, and b) Windows 10 has Continuum, which may be huge. It's early days in this sphere!