I think I know what's going to happen.
Microsoft is going to have two, and only two, OS's.
The first one will be a fairly unattractive, utilitarian operating system which will be intended mostly for developers. It will have the capability to run things like VMware or whatever virtual machine software they're using, and compilers and whatnot, because that's the platform that software--I'm sorry, apps--for the consumer-grade OS will be created on. It will have minimal eye-candy and will be intended to run on hardware that's either very different or much more powerful than most consumers have at their disposal. It will either be hideously expensive or mostly unavailable for purchase unless you happen to be a professional developer, and the average user probably isn't going to want it anyway, since it likely won't be much good for gaming or entertainment, unless you plan to run an operating system really capable of those things sandboxed within it.
The second OS will be the consumer-grade version. Your experience on the desktop version will be identical to your experience on the phone version, which will be identical to your laptop, which will be identical to your console/television, which will be identical to your tablet. It will be big and bright and shiny and colorful like a cheerful clown suit, and you will have many ways to customize the color and sounds, so that users who like fuschia backgrounds or flowers and harps or whatever will be able to rearrange it to their liking, using its handy touchscreen motion-sensitive interface. Grandma will be able to easily find her Facebook page, since the app will be right there--there will be no distinction between "online" and "offline," and the entire experience will be simplified to the point of "touch the button and it goes." There will be many games for it like Angry Birds: Chernobyl and Gears of Warcraft 4 and 5, and many apps for accounting and word processing, most of which will be entirely online and you may pay a monthly fee for as a service, with different levels of functionality based on your subscription level. Most storage will be offline, in the cloud, and you will not be prompted to save anything locally, because there may be no capability to do so. There will be no opportunities for piracy, since games, software, music, books, television programs and movies will never actually be able to be stored on a local hard drive in a form you have access to, and can be quickly deleted from your storage if they happen to violate copyright--and there may even be options to limit their access only to the person who purchased them to begin with, using biometrics. In any event, it will be flatly impossible to resell old or used software or games. It is possible that some or even most processing power will be kept offsite as well, and you will pay for that, too, depending on whether advances in broadband technology keep up. Your computer will be entirely locked down, just like an iPhone--you will have no access to the guts of the operating system, since you will not be an administrator of your own computer or anything on it, and will only be able to modify it in the few ways you are legally allowed to. Coding or modification will be difficult, inconvenient or maybe even impossible, since the consumer-grade OS was never intended to be a developer OS and any modification of the OS breaks the EULA you digitally signed by installing it in the first place. In order to do any of those things, you will have to uninstall it entirely and replace it with another OS that allows you to do so, with no guarantee that your computer's hardware will be capable of running it (See the recent kerfluffle with Intel and Linux), or jailbreak your own computer and run the risk of turning it into a very expensive, postmodern boat anchor with the very next involuntary update or patch.
On the other hand, I could be wrong.
