The issue, as I see it, is that many developers in the Microsoft ecosystem consider Microsoft to be a trusted benefactor and are detached from the realities around software engineering today. Such developers often won't touch concepts and implementations which have been proven outside of Microsoft until they get the blessing from Redmond with a Microsoft-built implementation.
The net result is that for at least a decade or more, many Microsoft developers have lost the independent judgement needed to filter solid technologies from the over-hyped ones.
The truth is, Microsoft is a business like every other. And they have changed with the times in that they experiment a little more and admit failures a little sooner. The challenge for Microsoft is that they are still viewed as the "safe bet" by many in their own community and they have to reconcile this reputation among their base with their own ability to evolve.
I suspect that a deeper issue here is that Microsoft developers believe that Microsoft is as permanent as things get in software, and by extension that everything Microsoft releases will last forever.
Realistically, most EOL'd Microsoft development platforms had been in their period of being officially supported for no less time than it takes an open source platform to go from being the hot new thing to something that's barely worth mentioning on your resume anymore. And Microsoft still offers a lot of continuity - XNA and Silverlight may be dead and WPF might be on the way out. But those C# skills you learn on the old platforms are still usable all over the place, including in Unity (for game developers) and with Xamarin (for mobile). And those XAML skills will still hopefully be useful with WinRT. By contrast, it'll probably be a much bigger deal to switch platforms when Ruby finally becomes passe. For one, it'll take learning a whole new programming language.
Before I get jumped on, I should hasten to say that my intent isn't to criticize any open source for anything. It's to criticize the Microsoft community for developing an attitude of complacency and perhaps even entitlement.
The net result is that for at least a decade or more, many Microsoft developers have lost the independent judgement needed to filter solid technologies from the over-hyped ones.
The truth is, Microsoft is a business like every other. And they have changed with the times in that they experiment a little more and admit failures a little sooner. The challenge for Microsoft is that they are still viewed as the "safe bet" by many in their own community and they have to reconcile this reputation among their base with their own ability to evolve.