With AMP, Google could preload and pre-render sites, so things like swiping through a carousel between search results was instant.

That’s not possible without building an AMP page since it requires being able to safely serve off of google’s domain.

Thanks, that sounds like a neat feature. Regrettable than neither the Wikipedia summary, nor the Google Search AI overview, nor Google's own official summary page for AMP, [0] make this clear.

[0] https://developers.google.com/amp