You cannot give developers a nice technology and take it away and then expect them to flop over to HTML5/Javascript.   Someone else will fill this gap and if it is not Microsoft then they will start hurting.  Maybe Microsoft becomes the next Kodak where it thinks its king and film will last forever.

In fairness, in most cases they expect them to flop over to WinRT, which is still XAML, which is the biggest learning curve for Silverlight anyway. What's gonna happen on the web, of course, is anyone's guess.

Anyway, I still think there's something else to it. With all the rumors that they're about to push Silverlight to the Xbox it seems unlikely that they'd simultaneously pull the plug.