Javascript is unneeded for vast majority of use cases, or is needed as an optional extra (like client side form pre-validation). 99% of existing Javascript on most websites is garbage that actually detracts from user experience; and it tends to grow like cancer - where one could get away with some nice enchantments on an otherwise Javascript-required website, one tends to instead end up with a slow, bloated monstrosity with pointless animations, sliding, etc. that cannot be used in multiple tabs, doesn't have capacity to link to a section of itself, etc. (see Chase banking website, for example)

And that is why I personally think no-JS should simply be an ADA-based legal requirement, like handicapped spots. That would force the usage patterns to move in the right direction.