You pretty much come to the right conclusion in the end. In reality, nobody is forcing us to use WebPack, Yarn, React, etc. If an employer thinks I can't learn most of these tools on the job, then that's not the right employer for me. Although I don't think you're entirely right about Gulp, I tend to start most of my projects with Gulp, Express, and Handlebars because those are the tools I like to use. Nobody is stopping me from using those, nor will I ever be chastised for doing so. If any tool becomes useful to me, I will learn it regardless of its popularity. Well, unless support needs to be a serious consideration.

The "churn" we feel is really just a confusion from having so many new options while only wanting or needing a handful of simple/stable ones. This is troublesome because there aren't market forces(per se) or companies with researchers to limit our choices for us, like a spaghetti sauce company figuring out which 3 flavors of sauce to sell. If you can distance yourself from needing to be relevant, you'll be fine. Learn JavaScript and keep up with browser and Node.js advances; that's really the majority of what we need to do to stay relevant.