The difference between webforms and MVC was huge... (no more postbacks)

But i think Microsoft is slowly finding the correct way of doing things and yes, there is a lot of influence of NodeJS (Owin) and RoR (Scaffolders). But it's easier to change between the same platform (and still using C#), then changing between web technologies.

The above user wasn't required to switch to Silverlight, some web applications in my company still use Asp.Net 1.0 and it still works (not my projects, thank god)

Good point, I'm thinking in terms of code quality, which can be seriously improved by using newer language features. I mean, you could write C# without using generics or LINQ or extension methods or a dozen other meaningful improvements, but I can't imagine someone doing so on purpose.