You can disable it for now, but there are already some companies building their entire websites in AMP like independent.co.uk.
A better solution than AMP would be to only consider raw page speed, and then use a neutral schema markup for whatever extra features Google wants to display in Google Search.
A subset wouldn't require you to load js to use built-in features like forms. A subset would just remove features or elements, which would make the whole load a js lib to make it work superfluous.
AMP is not a subset of HTML. It's a superset of a (badly defined) subset of HTML.
A "subset of HTML" that by specification is required to load Javascript from a central CDN, and by specification will let you wait multiple seconds before it shows anything if that JS doesn't load, even if perfectly usable content is loaded already.
