Except React decided to change to hooks and break all their docs. And Vue decided to break things with ver 3. And then there's Next. No, Nuxt. Wait, no, it's Nest. Or Sveltekit. It's not frontend anymore, it's more like frontend on backend, but not quite. No, is both now, we got interactive islands. And web components. Oh and wasm. Or was it blazor? And we have webpack. No, Vite. Or Parcel? Almost forgot, it's esbuild this week, innit?
But other than that, yes, frontend is pretty stable now.
I think you've accidentally proven his point. Half the things you've mentioned have been around for half a decade at this point, and pretty much all of them have existed for at least 2+ years.
Frontend is still a fast moving space with a large ecosystem - and I get for some, that's not ideal. But this 'frontend fads' meme isn't really reflective of the current reality.
Rust, which is the greatest new hotness in the backend world is from 2015.
Other major languages in the backend world are at least 2 decades old (C#, Java, Python, C++, Ruby, etc).
C# with the .Net framework is an interesting example. Microsoft realized their original windows only approach was a dead end. They created .Net Core. But someone moving from .Net framework to .Net core didn’t have to relearn much at all, beyond initial config/bootstrapping, and which subset of the APIs had been implemented, because MS completed the implementation in stages.
On the flip side you have React, where you’re ostensibly using the same library for a decade, except halfway in between they made a change which completely flipped how developers weee supposed to use the library.
I mean, that's just a laundry list of buzzwords. Yes, these are all things that exist, but that doesn't mean anyone has to learn them or that they're even used in a significant number of real-world codebases. It's like complaining about web development in Python, because there was Django, then Flask, Bottle, CherryPy, and now FastAPI, or Starlette, or Starlite, and Pydantic or attrs or dataclasses or whatever else. In practice, there are some fairly clear ecosystem best practices for the majority of cases, and a bunch of different alternatives because every ecosystem loves trying out different ways of doing things.
But other than that, yes, frontend is pretty stable now.