That exact caching has to end.
They can offer to do a CDN like CloudFlare, but make it optional.
I want to ensure that not a single bit of my data ever runs through Google's infrastructure, while still getting all the same benefits as if it did.
If Google treats sites different just for using an AMP Cache, then I'll have to send another complaint to the EU Antitrust committee.
My pages actually increased their loadtime tenfold when I tried them with AMP — they're tested on a HUAWEI IDEOS X3 on 64kbps GPRS. AMP increases load time to over a minute. (On a modern phone, with a modern connection, my pages are obviously also faster — I'm also testing with a Nexus 5X on 100Mbps 4G)
I can't just massively increase load time for pages just for a better ranking in search results, this shouldn't even be a choice.