That is exactly what AMP is attempting to be. It's a subset of HTML and CSS which guarantees that the site can be preloaded in a privacy-preserving way. There are a lot of things sites want to do that can't be done in pure HTML and CSS and allowing full use of JS would be incompatible with this goal, so that gap is filled with open source libraries.

(Disclosure: I work at Google on Ads, and I work with the AMP folks a bunch. Speaking for myself, not the company.)