This is a specific definition of "small web" which is even narrower than the one I normally think of. But reading about Gemini, it does make me wonder if the original sin is client-side dynamism.

We could say: that's Javascript. But some Javascript operates only on the DOM. It's really XHR/fetch and friends that are the problem.

We could say: CSS is ok. But CSS can fetch remote resources and if JS isn't there, I wonder how long it would take for ad vendors to have CSS-only solutions...or maybe they do already?