You're overlooking a lot of powerful applications that need SOMEthing to work client-side. Markup.io, recently featured here, is not the sort of application that can post-through to another page to fix. One could argue that it might also work with Flash, or ActiveX, but I'm only even mentioning them to head off somebody else from doing so, as that's hardly a solution.
I suppose it could be implemented as an Applet, but what's important is that Markup.io is exactly the sort of thing that Javascript exists for, really. And yes, disabling JS will break it, completely, and yes, I think that's perfectly forgivable.
On the whole, I agree that my blog should degrade, and data-entry type applications should work as well, but saying that everything should is completely overlooking an entire category of application for which it's perfectly acceptable, in my opinion.
