There's a lot of justify your platform going on at the moment. I see Mike Taulty has weighed in on the subject.
The thing is that the 'HTML5 lobby group' aka Apple and Google, have a lot to gain by denigrating Silverlight and Flash. iOS doesn't support it and Google's core strength has been by commoditizing the web with its thousands of JavaScript programmers. HTML5 is all well and good, but in the rush to save the universe people are getting a bit blind. Add these two behemoths to the voices of the thousands of "script kiddies" that consider a couple of lines of copy and pasted PHP and JavaScript programming, and you'd think we're reached software Nirvana.
The truth is HTML is still HTML and Flash and Silverlight are not just about streaming video.
Even using a better browser like Chrome or Firefox, how many times have you been frustrated waiting for a page to load? Have you gotten irritated, or worse – had to apologize to a customer, while trying to find what you were doing in a mass of tabs or accidently closed the wrong tab and lost their state? What about sitting waiting for something to happen while JavaScript has a meltdown and there's no way of knowing? That's just from a user perspective. From a developers view, JavaScript is a complete PitA, and trying to do LoB or Verticals levels of complexity is a killer, never mind the testing time.
Then there's the whole question of running disconnected. Page storage is all well and good but what happens when *shudder* you have to move to another page? What about device integration?
The truth is Silverlight (and Flash) presents real value to application developers but is a bit difficult to quantify if you haven't felt the pain of trying to develop large HTML apps.
But that's just me.
