The desktop is moving in this direction as well. Your example of OS X is shaky in particular, given the App Store. Even if it's still _possible_ in the future, acquiring apps outside the official channel will be exceptional, done only by enthusiasts.
The time has come when Microsoft does think they can get away with it. All Metro apps on Windows 8 will have to go through their app store approval process.
I really hate this trend. That's one thing good that Java brought to the table. Everyone had Java installed, so getting my apps "installed" was just a matter of getting them downloaded.
If only this was the year of the Linux deskto... oh, nevermind.
This is why I always help people crack their devices, even if they're mainly interested in warez. We need to ability to work around censorship which we'll lose if we let ourselves be locked down.
