Nearly 40 years of stuff.
People iterating on a problem space over time is the best way we have found to improve things.
The JS ecosystem is not that old and also attempts to solve hundreds of unrelated problems like running software without peoples consent.
As much as I don't like all the choices they've made, the choices have been the result of iterating on the problem space over time.
And... yeah the consent thing is messy. There's a kind of implicit consent in knowing that a user that does not consent can block scripts. But then it can quickly become coerced consent if there's some IRL reason you need to use the page and it absolutely does not work without JS.
That said, I'm a JS-webapp UI guy. Partly that's just what I've built my career on, largely because it was the new field emerging as I was coming up. I could learn things quickly and convert what I learned into a salary. But the second reason is that I'm disillusioned with HTML as the wire format for the web. If you choose to render HTML on your server, you're centralizing costs in a way that will eventually force you towards an extractive relationship with your users. Not only are you centralizing the cost of rendering and transmitting the HTML, but you're also centralizing the cost of building and maintaining the UI layer.
This is (partly) because HTML failed at being a semantic language. There was a brief flicker of hope with XML and XSLT -- for a hot second you could write a compact semantic document and send it over the wire. No longer...
> The JS ecosystem is not that old
I hate to tell ya this... LiveScript was renamed to JavaScript in 1995, and the first ECMAScript standard was published in 1997. So not 40 years old, but 31 years old.
NodeJS (liberating JavaScript from the browser) was first released in 2009... so again, not 40 years old, but old enough to have a drivers license.
I agree with you on the other side though: despite the language being relatively old and stable, it feels like the wheel's getting reinvented over and over again and "this will be a good enough pattern for the next decade" hasn't ever really shaken out, unlike Lisp or even Python.
I think I need to update my sales pitch for the passage of time. Emacs is probably closer to 50 now.
Also notable that the way changes are introduced to the different languages is so different that this is just hard to really look at. Notably, elisp of today is not dramatically different from elisp of 20 years ago. JavaScript? Basically a brand new language after ES6+.