The behavior you describe occurs if the useragent blocks the URL https://cdn.ampproject.org/v0.js which does not have anything to do with ads or analytics.
Certainly an ad blocker can be used to block any URL, but I don't know of any that block this one by default. If there are any, let me know and I'm happy to file issues to get that fixed!
If a user chooses to block this particular resource which the page needs to load, then the page still loads after 8s.
Similarly, if the site owner chooses, they can run the AMP Toolbox optimizer (https://www.npmjs.com/package/@ampproject/toolbox-optimizer) which lays out the page server-side and removes this CSS flash for most documents. Some documents can't be laid out until the viewport size is known.
People who block JS by default but who don't want to completely turn off JavaScript encounter that 8-second delay. (I'm using "ad-blocker" loosely -- it refers to any kind of tool that blocks ads and tracking. On my computer, it's blocked at the hosts level in addition to an add-on.)
Some people don't want to load resources from Google's servers, and they shouldn't be punished for it. That JS file isn't needed for AMP pages to load. People don't need to load JS to read text and view images. I don't think there is any reasonable argument to have any users hit an 8-second delay.
Without the Javascript file, the images will not load. AMP loads images using a custom element <amp-img> which has performance benefits such as lazy loading of images until they are close to the visible viewport and guaranteeing a stable layout that will not cause the elements on the page to jump around. The downside is that until Javascript is loaded, these images are not available to the browser.
Not seeing images is better than not seeing the page at all. People who block content know that things sometimes don't load. There is no reason to block loading of the pages for 8 seconds.
You're probably not their target audience anyway (read ad money stream) so they don't really care if you have to wait on content or don't see it at all. Google et. al. just see you as a parasite on the system.
It seems like the AMP delay is there to punish people who block that JavaScript loading from Google's servers. I can't think of another reason why there would be an 8-second delay for any user of a technology that (dubiously) is supposed to be about speed.
I solve it with a browser extension that redirects AMP to HTML, but that solution might not last forever.
One problem is that Google wants AMP to replace HTML. I've already seen AMP pages in the Google search results (on desktop), and at least one large website so far appears to be built entirely in AMP.[1]
Google already sends desktop users to Wikipedia's mobile site from some of their listings, so I wouldn't be surprised if Google eventually starts to send desktop users to AMP pages. Google benefits when people visit AMP sites, because Google will be able to spoof the domains and serve the content themselves, giving them increased control over publishers.
[1] independent.co.uk, but they removed the CSS that delays page loading.
there's a good reason for that because if you don't google can track you everywhere by IP, or at least have a reasonable guess that it's you or someone in your house.
The AmpProject is without question controlled by Google, so I reject your claim that it "does not have anything to do with ads or analytics".
The company is an advertising company. If 90+% of your revenue comes from one thing, that's what you are. Anything else is a gimmick.
That tech fanboys continue to ignore or refute this fact about Google just shows how much Kool aid they've consumed, I assume by skipping the drinking part and going straight to Kool Aid baths and Kool aid enemas.
Blocking third party resources on a site is not a "bug" that needs to be "fixed".
Certainly an ad blocker can be used to block any URL, but I don't know of any that block this one by default. If there are any, let me know and I'm happy to file issues to get that fixed!
If a user chooses to block this particular resource which the page needs to load, then the page still loads after 8s.
Similarly, if the site owner chooses, they can run the AMP Toolbox optimizer (https://www.npmjs.com/package/@ampproject/toolbox-optimizer) which lays out the page server-side and removes this CSS flash for most documents. Some documents can't be laid out until the viewport size is known.