Requirements Exceeding Web Capabilities

Let me start off with the fact that I like HTML. I like JavaScript. I like CSS. I'm rather proud of my abilities in combining these technologies to make some really interactive sites. The problem is that I keep seeing requirements come down that make using these age old and proven technologies extremely difficult. So there's prototype, scriptaculous, JQuery, Dojo, GWT; I could go on and on. And to a fault these libraries do ease the pain. Well, some of them. Some of them actually cause me more pain.

I'm leading a project now and I spoke with one of my developers and asked him if he thought this would make a really great Desktop application. He agreed. Unfortunately, it's not what the client wants. In fact, Its not what any client wants these days. Its all about the DubDubDub. Enter Flex and Silverlight.

I don't dislike Flex and I know it has been around for a year or so and it is going open source, yada yada and I've not even glanced at Silverlight so I won't bother commenting on it aside from saying it locks you into the .NET world. And looking at Air, linux is once again an afterthought for the flash guys.

It seems to me that web developers are sitting in a very difficult era in web development where clients want the bells and whistles of a true rich client application that runs in a web browser but aren't willing to commit to new technologies (Flex, etc) that actually make these applications possible. What's a developer to do?