It's not that tough to keep up with FE. React has been dominant for closing in on 10 years now. ~2015 was probably peak framework fatigue. If you left the industry in 2016 and came back now, you could probably get productive and you would even recognize a lot of the tools.
The HN meme is that "Well ackshually you could build Figma with ASP.NET Forms, just like we used to do back in my day." That just doesn't resonate with anyone doing the work day to day because applications themselves (not necessarily the front-end tech) have a much higher bar today.
The idea that React 10 years ago is the same as React today seems to be highly oversimplified. React was simple, then hooks were added, and state management fads that turned something simple and intuitive into an IQ signalling exercise. At least that was the case when I switched to back-end only dev a couple of years ago. And of course other parts of the stack also keep evolving: TypeScript (which is probably a positive, but again, I know people who do bizarre things with the language to build their "nerd cred").
Off the top of my head there was also Grunt/Gulp/Webpack/whatever is around now. NPM-Yarn->NPM. Angularjs->Angular 2.0+.
How many different CSS positioning methods are there? (that's what led me to leaving front-end, I was expected to do a pixel-perfect rendering of a design for a time-critical back-office app for some reason).
I can literally spin up a globally replicated service with as much scalability as I need using 1 programming language within an hour today. I doubt that was possible 20 years ago.
We used to have to pay 5 developers to maintain all these moving pieces, but now it only takes 1 developer to maintain all this stuff because so much of it has been simplified.
It used to be if you could find a solid engineer with some vague aesthetic sense they could efficiently carry something through from conception and design to completion.
These days the scope of frontend development has increased to the point where learning and staying on top of it has become too large (in my opinion) for most people to do while also becoming and staying highly competent in everything else.
A “full stack” developer these days is supposed to understand frontend development, backend development, systems administration, cloud operations, and what else? All of these are massive areas that are constantly shifting.
By way of analogy, we used to have the town barber handle haircuts and shaves but also surgery because the main skill to master was precision with a blade. Then as the scope of being a surgeon expanded to include things besides being able to cut precisely, that became its own specialization. Further on, even within surgery each area of the body started to require so much specific knowledge that we further broke that down into all the different surgical specialties (heart surgeon, podiatric surgeon, brain surgeon, etc).