I love how everybody always takes the "fun" argument. It's such an easy solution. But everybody only ever gets it half-right. Because I can tell you that it's not fun for the Windows and OS X people either. They do it because someone figured out how to make money with it and then they paid people to do it. Nobody does backwards compat crap on those platforms without getting paid for it. And nobody pays for Linux.
And it's the same thing with Ingo's argument. Sure, if you want to build a platform that is about making money, Ingo's plans are awesome. You make sure everybody has a corner where he can make money in and doesn't need to talk to each other. And then everybody makes money.
But none of the Linux desktop distros make money (some want to, most don't even want to). For them it's a collaborative effort to create whatever (I'm not really sure what for most of them, but they enjoy themselves). So they are wildly successful and what they want to do. They just don't make for a great mass-market desktop.
Fwiw, the only Linux distro that I know is making money is RHEL. And as Ingo points out, RHEL does exactly the right thing.
TL;DR: The first thing you'd need to solve is the distro. This has nothing to do with the desktop.