VNC is not the only game in town, of course. X Windows networking is, indeed, very very cool. But it's been a very long time since it had any sort of monopoly over remote applications.
Windows users have been enjoying Windows-apps-over-internet for many many years now.
Does anybody have a good how many people use 'Go to My PC'? It's a huge number and they all do it over the internet and it works far better, far easier, then X Windows does.