I think you may have typo’d, but just in case: 1.1.1.1 does not send EDNS ECS data, specifically because of the privacy concern. So the hypothetical secondary

I think you may have typo’d, but just in case: 1.1.1.1 does not send EDNS ECS data, specifically because of the privacy concern. So the hypothetical secondary resolver would need to send that data, for people who aren’t concerned about the privacy implications / want to get to archive.is. Given CloudFlare’s stated message of prioritizing privacy, it seems unlikely they’d stand up infrastructure that behaved like 1.1.1.1 except that it leaked more private information.