AMP was only ever needed because so many made their pages so artificiality heavy in the first place and had no incentive to make them lighter.
AMP SEO advantage is a great incentive to make them lighter. The thing is, Google could have pushed their algorithm toward performance more and make it clear on their page too and have the same effect. They just found a way to get more control from it too.
AMP was a very calculated move on Google's part. The narrative of "we're only doing it to help our users avoid the bloat" when everyone agrees that bloat is a huge problem works very well.
Didn't they? I mean, I figure everybody read the case studies about page load time and user abandonment. My experience is that those who built a leaner mobile version of their desktop site were also mostly the ones that built an AMP version (WP + "I'll just install a plugin and see what happens" left aside), while those that never cared about mobile users still don't.
Does AMP deliver better rankings? I haven't seen that on sites that I'm affiliated with, but that may be niche specific or the improvement wasn't big enough to go from 4 to 3 etc.
> that never cared about mobile users still don't.
News website still have multiple MB per page and they all got an AMP version which is much more lightweight.
> Does AMP deliver better rankings?
That's a good question. I do know that Google would show news stories with AMP at the top first, but that was part of a different widget. I do remember reading that it helped ranking.