At least for me "year of Linux on the desktop" is not about "can Linux be used on desktop" because of course it is possible. For me it means Linux being a popular choice on the desktop. That it is not.
I'd also note that Windows is ubiquitous, but hardly popular. People who know about computers tend to have not-so-great opinions of both MS and Windows while people who don't know about computers are only using Windows because it's what comes bundled with their machine. For the rest, MS has directly or indirectly paid to keep the software they need stuck in the Wintel duopoly (though that is also slowly changing).
Linux is widespread on basically every single type platform out there, if not dominant in most of them. The only where it's currently lagging is laptops, and of course not as popular as other OSes on desktop. But on the rest of the platforms out in the world, Linux and various derivations is very popular.
EDIT: I think it is pretty obvious that we are not talking about servers and patient monitors here, but rather desktops and other enduser devices.
Yeah maybe it's the UNIX kernel, but it's not the end-user Linux experience, which is what 99% of the people talk about when they say it's not the "year of Linux on the [insert platform here]".