When AMP was introduced I assumed the actual content would be loaded from the canonical URL anyway. This whole in-between caching layer G introduced is very weird.
Also, I think what AMP was pitted against--Facebook instant articles--no longer exists, or at least doesn't particularly matter (now that FB is several pivots beyond the whole 'newsfeed is full of articles' stage).
One way to think of AMP is as a solution to "When people click on links from search the pages often load very slowly. Can we make this instant?" Any preloading based solution has to involve caching, because otherwise sites could learn that they had shown up in your search results without you having clicked on then.
(Disclosure: I work at Google, not on AMP, and I'm only speaking for myself)
While this might have been one of the reasons, most likely from the (sometimes rather native) perspective of devs, I still attribute mostly malice to this whole thing and hope it gets them good in the whole antitrust issue. Even if it were just that, trying to tackle slow loading pages out of selflessness on Google's side, I can only say: None of your ducking business. Make sure your pages load fast, and then that's it.
> trying to tackle slow loading pages out of selflessness on Google's side
I'm not sure where you're getting "selflessness". The faster pages load from search the better people's experience of using search is. This directly benefits both Google and people who use search.
Preloading in the browser? I guess... my understanding was that the major benefit of AMP is the stripped-down markup. eg. in AMP you can't have a giant background video, or a bunch of JS email opt-ins driven through live A/B tests... all the random stuff that slows down sites these days.
It was an answer to Facebook's Instant Articles, and nothing else. As a response to Instant Articles it's intent was to bend publishers to the company's will and create a tightly controlled walled garden.
Everything else is the result of that original decision. And the continuous apologetics for the myriad bad and malignant decisions are the direct result of that decision.
Also, I think what AMP was pitted against--Facebook instant articles--no longer exists, or at least doesn't particularly matter (now that FB is several pivots beyond the whole 'newsfeed is full of articles' stage).