Not sure there's an extension API that could make signed exchanges work either.
AMP takes control away from web publishers by forcing them to allow anyone to serve their content (signed exchanges). Publishers no longer have control over how their sites get served (for example, no more server-side logs, because Google has forced you to let them serve your site).
It allows large sites (like Google) to have more control over smaller sites by putting back buttons at the top of your website in order to take them back to Google Search. The related "portals" scheme is the new "can you open all external links in a frame?" and small sites are going to be hurt the most.
Publishers don't want to be forced into using "instant loading web pages" if it fundamentally breaks the nature of the WWW and takes control away from them and gives it to a few large companies (AMP caches).
Publishers have to meet users where the users want, and AMP is easily the best of the options because by implementing it once, publishers provide instant loading through multiple link aggregators. If I want to write my own link aggregator, I don't need the clout of a FAANG to get publishers to do a data integration for instant loading pages — I can just implement an AMP cache and use the AMP pages they have already published. AMP levels the playing field.
Google doesn't have a right to damage/destroy the Web or take control away from publishers so that Google can compete with Facebook and Apple. That is not a reasonable argument.
Publishers don't want AMP and the project would fail (as it should) if Google weren't strong-arming everyone to use it with a threat of traffic loss.
The Web is not a Google product, but Google is treating it like one. The company has seriously lost its way.
> Google doesn't have a right to damage/destroy the Web or take control away from publishers so that Google can compete with Facebook and Apple
The publishers get to decide if they want to integrate with Facebook, Apple, and all the AMP caches. The former two they have less control over because they only go to one company and don't have open governance.
> Publishers don't want AMP
They want the first two even less, but I don't see anybody complaining about that. As I said earlier, the problem for publishers is that users demand instant loading. AMP at least lets the publishers control analytics, ads, A/B testing, etc.
But we've gotten way off track again. Users demand instant loading pages. How do you solve it? Would you rather have Google require the publishers directly integrate with them as Apple and Facebook have done and not allow other link aggregators to benefit? Users also like RSS, which takes even more control away from publishers, does not allow above-the-fold loading optimizations for users, and has a much less rich experience, but nobody here has ever complained about RSS.