What I find annoying is that most of the websites that have the features consuming the broadband that you are describing ("autoplay videos, huge JS libraries, giant pictures, etc.") are just showing some text and a few pictures and video, and there is no need for them to require things like sophisticated js that make them slower - I am OK with a website that does 3D animation in js being slow, I am less tolerant with, say, quora's scrolling being slow.