I'm amazed this article didn't get voted up and get more attention.
The tldr; is that AMP pages are much faster than the canonical version of their pages, but effectively the only reason is that they are less bloated. In principle, you can make a faster-than-AMP page by not relying on JS for your critical render path, and by either using a decent CDN or applying certain optimizations yourself.
The difference between AMP and a simply de-bloated page is that you can get a manager to approve AMP, but not a simply de-bloated page. Also, Google boosts AMP pages, but not pages that are fast without AMP.
The tldr; is that AMP pages are much faster than the canonical version of their pages, but effectively the only reason is that they are less bloated. In principle, you can make a faster-than-AMP page by not relying on JS for your critical render path, and by either using a decent CDN or applying certain optimizations yourself.
The difference between AMP and a simply de-bloated page is that you can get a manager to approve AMP, but not a simply de-bloated page. Also, Google boosts AMP pages, but not pages that are fast without AMP.