> These public caches were much less wide spread than you appear to believe

You can keep your belief or disbelief. I ran my own, transparently with Squid on my FreeBSD PF gateway box back in The Day when we had a cable ISP with a restrictive data cap. I could send my roommate a link, or reload a link myself any number of times, and it never left the edge of my network after the first. It was really cool.

These days you don't even need to actively do anything for most operating systems' default configurations to loudly announce your presence and behavior to the ‘Room 641A’s of the world:

- Join any Wi-Fi network and your OS or browser (or both!) will automatically hit a well-known captive portal test URI.

- Most OSes will hit an NTP server that reveals the OS maker (depending on if it's Google's or Apple's or Microsoft's or the NTP-dot-org pool) as well as providing a heartbeat to tell the network you're still physically present when you make subsequent requests every ${default-periodicity} minutes following the first time sync following the captive portal check.

- Then once TLS' regressive dependency on synchronized time is satisfied, many default OS installs will hit a weather API whose transport layer is “secure” but whose response size is, if not unique among all possible geolocations that could be requested at the same timestamp, at least a piece of identifying information to combine with others. If I were NSA I would be making requests to APIs like Foreca for every possible geolocation at every ${change-frequency} seconds and storing every bit of sidechannel metadata about them forever for comparison with other recorded traffic.

- And most people's machines will announce their unique collection of software to the world through the act of making network connections to the known networks for the background update checks and “““telemetry””” (remember when the term was “spyware” for anything that remotely reported user behavior?) that have sadly become normalized in modern software.

I too ran Squid. It was more annoying than not (except for images, where I do think it was quite useful)

It seem you concede the point about survivability though?

Those other things that seem unrelated to the utility of HTTP vs HTTPS.