Back when WPF/WCF and Silverlight was being pushed, I was initially cautious. I gave the technologies a few tries and ended up not liking them. I didn't like WPF because it seemed like an over-engineered version of SVG. I didn't like WCF because I was used to Remoting and didn't need another layer on top to learn. I didn't drink the Silverlight cool-aid because I knew javascript would get faster and Silverlight would eventually get overtaken by more open options. My guess is many microsoft devs felt the same way and didn't adopt these technologies because if they did, these technologies probably would have made it into Windows 8.