Microsoft may go out of its way not to annoy us desktop users in the next major Windows release. According to Neowin, that release, which is known as Windows Threshold (and which may or may not be called Windows 9 upon launch), could disable the Modern UI interface altogether on desktop systems.
Word is that some pre-release builds of Threshold already do this. Those builds still serve up Modern UI by default on tablets, Neowin says, but they disable it by default on desktop PCs. (Users can still go in and re-enable it if they wish.) To access Modern UI apps, desktop users are expected to use the Start menu or the taskbar. And, oh joy, Modern UI apps run inside windows just like their non-Modern UI counterparts.
Neowin says this design is symptomatic of a departure from the "Sinofsky vision of [a] hybrid OS." Steven Sinofsky, the former President of Microsoft's Windows division, left the company in November 2012, shortly after the release of Windows 8.
Microsoft hasn't said a peep about Threshold yet, so this is still just a rumor. I think it ranks pretty highly on the plausibility scale, though. Windows 8.1 already takes the trouble of booting into the desktop by default on desktop PCs, and it adds title bars with basic window controls to Modern UI apps (though those apps are still stuck in full-screen mode). We've heard rumors about Microsoft implementing fully windowed Modern UI apps before, too.