The old web placed HTML and CSS as primary, and used JS for incidental tasks like form validation, or fixing up the back button. The big idea was "graceful degradation": sites were expected to work without JS, at the cost of (say) a server-side error instead of immediate feedback.

Modern reddit does not gracefully degrade: it requires JS to click buttons, to load images, to scroll, etc. Old reddit still works well without JS. So does Google for that matter.