Well, 3 points:

1) in most of your post you argue against the performance of VS2010 and how slow it is to edit XAML, not the performance of your Silverlight code/application. I take that it was as good as mine. And I think that this is what is being discussed here.

2) I agree that VS2010 is indeed much slower than previous versions, although I didn't experience something as terrible as you. But I am running it in a 3GHz quad-core with 4Gb of RAM, so...

3) Silverlight is a WEB client solution and that's the scope of this discussion and the post I answered. Correct me if I'm wrong, but I think frameworks like Django and Rails are server-side technologies and, as such, don't compare to Flash and HTML5, and are out of scope for this discussion, right?

Partially so. However much Silverlight might fill a niche for rich media, the fact is that 99% of the use cases will be for internal business applications, where it fails spectacularly. And in the case of ubiquitous media apps, it's simple: Siverlight is not nor will it ever be ubiquitous.