Here's the thing - people don't like to bring in a more complex technology simply to do exactly the same thing as they could do with a simpler one. They need to justify its presence in there somehow.
For instance, supposed you decided to re-implement hacker news with a client heavy javascript framework. Would you leave it looking exactly the same as before? Almost certainly not, you'd start using that javascript stuff, and (in my opinion), the end result would no longer be the simple, easy to read, text based website that it currently is.
That's the connection I'm getting at here (and once again, it's something I'm mulling over, not a hard conclusion I've reached).