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.
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.
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.
The 8-second delay is there to punish users who block JavaScript that is loaded from Google's servers (with ad-blockers) but still have JavaScript enabled.
Easy solutions: don't store photos and other files in your Google account and/or download old mail by dragging it to a local folder in an email client like Thunderbird.
A company shouldn't design its website with Google or Apple's visual branding as if it were locked into a closed platform. It also appears to be a problem with things like Flutter, though I haven't looked closely.
Google's browsers don't automatically load your websites with Google's visual branding and Apple's browsers don't load your websites with Apple's visual branding.
There's a battle between some of the large tech companies for appification of the Web at the moment, and that way of thinking is a trap.
The Web is open and independent. Google's and Apple's visual branding are not the standards of the Web. There are countless non-Google, non-Apple designs on the Web and they are not forcing users to learn anything new.
Sorry to disagree, but Material Design itself lacks aesthetic restraint and has accessibility problems with the constant flashing and animation, but that's another conversation.
Edit: I'm talking about the browser, not apps (though I don't like MD there either). I mean that websites shouldn't change their design based on the company that makes the web browser.
The open Web is independent of the browsing device. If you play Google's game of using their visual branding, you're making it easier for them to hijack the WWW into a Google product.
Having that as a default means that many people will implement it.
That's much worse than I thought. The Web is not a Google or Apple product, and your product's design shouldn't change based on which browser you use. That entirely misses the point of the open WWW. It's a terrible idea to build things in that way.
It would be nice if it were possible to not have it load Material Design by default. It's a bad idea in general for people to build their products with Google's visual branding. It basically paves the way for Google to become the entire platform.
I've organized about 500 events through that site. Charging attendees is a terrible idea that will kill Meetup.com and damage communities around the world in the process.
It looks like DNT is turned on automatically if tracking protection is on, so it probably doesn't identify you any more than "a Firefox browser with tracking protection on".
I was replying to the part about whether "you could actually use this as a main phone quite easily."
Some users might "need" Snapchat and Instagram (if we really stretch the meaning of "need"), but not 99% of them. A person who is willing to use old phones is probably more likely to not use those apps. I'm sure that many people wouldn't use them if it made their old phones work better. People who want those other kinds of entertainment apps can still spend money on new phones if they want.
URLs are also getting to be a problem. Browsers started to trim URLs, and it's resulting in web developers who are very savvy with computers who don't really understand how URLs work or that there is always a trailing slash on the root of a website and what it means.
Google is in the process of making it worse by hiding URLs in the search results. (It's also a security risk. Google's site-name detection often makes terrible mistakes and points users to malware.)