I see your point. On the page that I'm building, the mobile navigation menu is the only usage of Javascript and I think that's reasonable (desktop users are way more likely to disable JS than mobile users, for whom you should optimize anyway in most cases). Of course, there are other use cases where content is really dynamic (e.g. Etherpad), which you just can't tackle with only HTML & CSS.

In my opinion, it's those little things that JS is good at and CSS is (currently) not. JS is a tool, neither more nor less, and like with all tools, it's more important what you do with them than what tool you use.

That's not to say that I'm not in line with you that 95-99% of all JS code in modern web pages is bloat in the best case and acting against the users interest (like by spying on them) in most others, and I'm in no way an apologist for it. Condemning its usage altogether throws the baby out with the bathwater though imho.

Oh, and on performance: JS is pretty optimized today as well. A lot of waiting for modern web pages is due to loading of external resources, which would hardly be any faster if done in C*. In conclusion, we're blaming the language for what people do with it. 😉

* I'm not saying that 3rd party assets are necessary or good, it's just an observation