It's the fact that the entire Javascript community seems to suffer from ADHD and is constantly inventing a new tool that is marginally better than the last.
So for those us who don't do front end development we come back and suddenly have to learn 20 new tools.
If you assume that the entire Javascript community was one person or one coherent group, then yes. But it is not like that at all. You state this as if a single organization made grunt, then made gulp, then made webpack. This is nearly as absurd as saying "The entire programming community seems to suffer from ADHD and is constantly inventing new languages". People who are using grunt didn't pack-up their bags and move to gulp, then pack up their bags and move to webpack. Rewriting your front-end in a new webframework every 6 weeks isn't a thing that actually happens. That's as absurd as suggesting that after leaving ruby for node, your team left node for golang, then left golang for rust, then finally rewrote their application in elixir.
All these different tools solve different problems, or solve them under different constraints, or solve them in ways that better match their backend languages. There isn't some magical tool that everyone needs to jump to.
And ofc there's a big push for frameworks and languages over libraries, and libraries get coupled to frameworks, so anytime you do want to "upgrade" to the new thing, _everything_ goes with it.
You're operating on a false premise, the community is not a single entity. You don't oversimplify Javascript and pick the "standard stack", you have to do some basic research first. Maybe you need jQuery, maybe you need React. It would be pretty stupid to assume that all web development problems are nails then also assume the latest popular bleeding edge tool is a hammer.
I don't see any evidence of this. If anything, the source of most people's complaints is that the JavaScript community heavily prefers libraries over frameworks, which means you need to pick several libraries to build a project instead of
Are you sure you have any clue what you're talking about? I regularly "upgrade" parts of my stack without changing "everything." It's a huge part of why libraries like React are awesome.
I don't think any sane person would rewrite their apps everytime a new flavor of the month tool came out, but all this technical churn must make maintenance a nightmare.
^^^ THIS ^^^