In practice things like Twitter and Facebook, interactive programs, should really be just that - programs you run. If the interface is nigh static and the purpose is content interaction rather than primarily consumption you should be opening the Facebook program that gives you this interface and uses its client / server communication to feed messages to and from the interface, not provide the whole thing over the wire spread across document addresses.

And they are that on mobile. Who uses Facebooks mobile website? Everyone uses the app. The contention only exists on "desktop" OSes because Windows and OSX don't provide a UX workflow to push an app at user (at least they didn't when it mattered) the way a mobile site can. And that the app environments on both were way worse than the Android or iOS SDKs for making a dumb GUI for something like Facebook.

I do, just like I do with every app that might feel too comfy reaching out to my contacts. Not to mention how resource hungry it is.

If you think MFC, VCL, .NET are worse experiences than Android SDK you really never coded for Android.

But seriously, where do you draw the line between enriched documents and apps?

CSS? JS used for styling? d3 for visualizations? WebGL?

Websites have gotten so bloated that the only sane future I see is serving people unix + x in wasm.