Microsoft Xbox head Phil Spencer Getty Images/Kevork Djansezian When Microsoft launched Windows 10 in the summer of 2015, it came alongside a brand-spanking-new app strategy for the company.

Microsoft promised that with its new Windows Universal Platform (UWP), developers could write their apps once and they would run on any device running Windows 10 — including PCs, tablets, smartphones, and, eventually, the Xbox One and HoloLens holographic goggles.

From Microsoft's perspective, it's a grand idea for getting developers to take their Windows software and make it available everywhere, including the severely lacking Windows phone platform. With competition from Apple and Google only intensifying, it's critical to attract as many apps as possible.

Apart from a few big names like Uber, Hulu, Twitter, and Facebook, however, developers across all industries have been slow to sign on with UWP. Meanwhile, former Microsoft CEO Steve Ballmer says it won't work, and one of the biggest names in gaming slammed it as "the most aggressive move Microsoft has ever made."

Overall, developers are concerned that rebuilding their existing apps for UWP is too much work, while simultaneously giving Microsoft too much control over the PC software market.

But at a session at the Game Developers Conference, Microsoft Xbox Advanced Technology Group boss Jason Ronald explains why Microsoft's "journey to one platform" is good for game developers — and thus for all developers everywhere.

The ultimate answer: By smashing together platforms like the Xbox One and Windows phone together with Windows 10, Microsoft says that it's opening up all kinds of doors to help developers make a lot more cash and win more fans.

Smashing the Xbox

It's not news that Microsoft is bringing Windows 10 and the Xbox One video game console closer, including the fact that many former Xbox-exclusive titles will debut on Windows 10 with a cross-saving feature, and the extension of the Xbox Live network to Windows 10.

At his session, Ronald provided some more details on the future of that trend.

First off, the Xbox One is going to get the ability to run those Windows 10 UWP apps later this summer, with the Xbox Store and the Windows Store getting merged into one. Furthermore, UWP apps are gradually going to open up over the course of this year to run the more advanced graphics settings that PC gamers demand.

Plus, Microsoft also announced the "Xbox Live Tournaments Platform," a tool to let developers making Windows 10 and the Xbox One games organize their own competitive eSports leagues.

Earlier this week, too, Microsoft dropped the huge bomb that it's opening the door for cross-platform play between Windows 10, Xbox One, and the PlayStation 4.

A slide from Microsoft's GDC 2016 talk. Matt Weinberger/Business Insider

All of those things have a common thread: They encourage players to play more games for longer, across all of their Windows 10 devices, Ronald says. On phones, tablets, or the living room, Microsoft wants customers to never have to leave their games behind.

"We want all your players to stay in your game," Ronald says. "With Xbox Live, we want people to play games longer."

It's an important concept in modern gaming. In the early days, developers would release their game and leave it at that; modern gaming involves supporting a game for months or years after launch with additional paid content or subscriptions.

All of which means that if a developer can keep players playing, they can make a lot of money without having to reinvest resources in creating a new title. Indeed, Ronald boasts that Microsoft made 4.5 times the amount of revenue per Xbox Live-connected device in 2015 than 2014, with twice the number of paid transactions.

All about choice

In a broader context, Ronald says that the whole push towards UWP is about letting developers choose where they sell their app, and to whom.

"It shouldn't be easier to hit one platform versus another," Ronald says.

With regards to gaming specifically, Ronald says that there's no reason a developer can't use Universal Windows Platform to make a game that's just for the Xbox One.

Microsoft is working hard to make a range of tools and features available to make building games on Windows attractive, regardless of whether or not you're actually investing in the PC market, he says, with the goal of simply making UWP the best place to build games.

And with the merger of the Windows and Xbox stores, it makes it easy to start selling your UWP to the 200 million-plus Windows 10 devices and 18 million-ish Xbox One consoles out there, too. Better, it makes it easier to move your apps to new Windows 10 devices like the HoloLens, even as they're released.

"There's stuff we haven't invented yet," Ronald says.

Microsoft HoloLens. TED

And with Xbox Live as "the connective tissue between devices in our ecosystem," Ronald says, it's going to be easier to keep stuff like saved games and purchased goods consistent between platforms.

It's absolutely worth noting that all of this is just the gaming-centric version of Microsoft's strategy with its Office 365 suite — keep things consistent across devices, everywhere, with services on the backend.

And while Microsoft is going after game developers hard, it's only because gamers have proven themselves time and again to be the earliest, most bleeding-edge of adopters.

If Microsoft can get game developers on board, it's going to pave a nice path to future success. And that means unifying the platform to make life as easy for developers as it possibly can.