Potentially. However, <noscript> tags can be used to deal with some of this. Most web pages probably won't do this though.

AMP is not supposed to necessarily replace existing pages, but can rather be created by publishers as lightweight/performant alternatives for mobile visitors arriving via Google Search. Hence why you can declare

    <link rel="amphtml" href="/yourampversionofpage" />

in the normal page.

Those with JavaScript switched off probably won't be suggested the AMP pages in Google Mobile SERP.

So you could serve the JS-optional pages to all clients, progressively enhance for JavaScript users and offer AMP pages to mobile JavaScript users.

haha :) I didn't even realize :) I've been running NoScript (in addition to my usual bloat-blockers uBlock and Ghostery) the past two weeks, to determine the trade-off between convenience and CPU/responsiveness on my low-end laptop (so far: so good!).

The crazy thing is that the demo-page actually loads quicker with NoScript on. Okay, so I didn't see the images (and because the text was Lorem Ipsum, I didn't realize they were missing), I'm on a high-bandwidth connection so unless the images are secretly huge, the images on their own shouldn't be too much of a factor to account for the difference.

So in other words, while AMP may be a useful line in the sand for responsive guidelines versus corporate politics / environment / product managers / etc, it's no replacement for just writing lean and efficient code in the first place (if at all possible).

edit: turns out the comparison wasn't entirely fair because obviously I didn't have Google's JS code cached. On the second load there's less of a difference.