Thank you, thank you for sharing this. There is so much I'd like to express about this...

But won't be able to state that clearly in a comment - this needs a proper post.

For now I just say this - I think we really need to keep the web more KISS, really. There is a lot of trendy stuff happening and it is dangerous when we start treating these trendy things as "best-practice" and copying them everywhere, when in fact they are counter-productive and even toxic at times. A great example of this is infinite scroll (diaspora's frontend has this same antipattern) - no way to link to a specific point in the list of items, no way to know what is the total number of them, and the back button is (usually) broken.

I'm trying to treat JS as an optional add-on with the stuff that I build, as much as I can. In one of my projects I did implement a page that would load parts of it via JS when the user selects an item in a list, but if the user did just visit the url directly, the server sends full HTML instead. I don't think this would be a performance difference, but rather a way to avoid full page reload when only part of it actually changes.