Aside from all the problems this would cause with long-lived single-page applications and legitimate uses of high bandwidth (YouTube, Netflix, streaming radio,

Aside from all the problems this would cause with long-lived single-page applications and legitimate uses of high bandwidth (YouTube, Netflix, streaming radio, etc), I think you'd run into the same thing as the comment you're replying to is getting at: developers will find a workaround, and it may be worse than the thing you were originally trying to prevent.