This is exactly right. Imagine a hypothetical where Microsoft created AMP - no one would use it! The technology itself sucked. The only reason some publishers adopted AMP at all was to get/maintain favourable placement on Google, the only search engine that matters.
I'm just hoping that the death of AMP on the web will also kill Google's ambitions for rolling it into Gmail[1].
The idea of a proven-safe subset of HTML with no custom JS that's suitable for adding interactivity to emails is actually really interesting to me, and I hope it continues. It's been really great to be able to reply to Google Docs comments from within my email client, and the same things that make AMP good for rehosting make it a good foundation for interactive email.
I'm just hoping that the death of AMP on the web will also kill Google's ambitions for rolling it into Gmail[1].
[1] https://developers.google.com/gmail/ampemail/