[beagle3]

Except ...

Some things only work in Silverlight, some only in WPF, and mixing both at the same time is a royal pain.

There are a LOT of bugs and regressions in WPF4 that are "wontfix", were supposed to be fixed in 4.5 or 5.0, but that's never going to happen. (Google "wpf 3.5 4.0 bug wontfix" to see a very incomplete list of regressions. I've met some of these myself, and some that are not on the first two pages).

And lastly, unlike Silverlight (Mac or Win, no Android, no iOS, no Linux), HTML5 is much more widely available (and with an easier graceful degradation path). The only place where using WPF or Silverlight makes sense today is when your target audience is using a locked down system - e.g. an enterprise with tightly controlled client machines. Otherwise, it's a no-go just from this perspective.

I didn't find the learning curve intimidating, FWIW. But the experience with using and deploying me scarred me.

[JRobertson]

I agree that HTML5 is much more available. I wouldn't recommend a silver light app for any consumer based product. But I would have for enterprise applications if it was going to continue to be supported.

The lack of support killed off the language, not the language itself, IMO.