My understanding is that Silverlight is being used pretty heavily by some organizations to build basic internal web apps. They aren't using features that HTML

My understanding is that Silverlight is being used pretty heavily by some organizations to build basic internal web apps. They aren't using features that HTML doesn't have, instead they just want the data-binding features of silverlight and to stick to XAML/C#. This may be cost effective in the short run, but the author has a point. In five to ten years, these apps are going to seem incredibly outdated and browser support is not guaranteed.