If it's just your hobby site... great, develop it without JS.
But if it's a site people pay to access (or requires ads) and they expect some functionality - like Youtube or Netflix say - I don't think this is possible.
As far as I understand it, YouTube and Netflix are a nicer UX with JS but there’s no particular feature that would kill it completely.
Like, for example, I thought that you can play HLS* manifests from plain HTML5 video tags.
EDIT: I was thinking of HLS and not DASH
But HLS has wide support on mobile browsers, and on desktop Safari. (Source: https://caniuse.com/http-live-streaming.) So YouTube should in theory be able to support JavaScript-free playback for many of its users.
Do you think that difference would materially affect whether YouTube or Netflix could exist as a website in a meaningful way without JavaScript?
By meaningful: would it fulfil its core competence of finding videos and streaming them to the browser?
Even things like voting and commenting are fairly straightforward to do basically, though you could do vastly better with an auto-resizing iframe (https://github.com/whatwg/html/issues/555) which would basically allow you to load new content into the document with a click (though it’ll clutter the history and make the back button behave surprisingly, see also https://github.com/whatwg/html/issues/6501 on that).
Youtube actually uses this capability specifically. If you add a Youtube video to a queue, it switches to a picture in picture mode where you can navigate while the video is still playing.
The only other technical challenge is handling animations between route changes. There's a browser api in progress (the shared element transition API) [2], that will allow animations during navigations without client side routing, but it still requires Javascript. Navigation animations are arguably just purely aesthetic though.
[1] https://youtu.be/860d8usGC0o?t=299
[2] https://developer.chrome.com/blog/shared-element-transitions...