What about the other part, the vast quantities of information that will never be encrypted because the sites remain but the people have moved on or are gone? Why does that deserve a knockout punch?
Would you clarify what you mean here?
We've yet to see if users will either (A) follow the on-screen, flashing red prompts, or (B) be trained to click through the warning screens due to their sheer prevalence.
Even in case B, it's a non-negligible probability that browser vendors respond by disallowing click-through. Just another step towards (re-)making the web into a nice, safe walled garden.