One advantage of autotools is that at least a lot of the skills are transferable. Shell scripts and Makefiles (and OK, M4 isn't so popular these days, but it was for a reasonably long time) are things I can learn and use everywhere, not just this project, not just C projects, not even just development.
I don't learn any transferable skills writing Webpack or Babel config. They don't even necessarily transfer to the next generation of the same tool.
I would also take a stable autotools over an unstable autotools, and I consider most of JS-land roughly equal in usability to unstable autotools. Autotools was also not that bad on the happy path where you were targeting, say, the top five POSIX systems over ten years - and maybe you didn't even need it at all, if you didn't need the performance from distinguishing each platform's best supported fd polling variant. Vs. JS, which is still bad even if you're only targeting evergreen browsers, because maybe you're stuck trying to integrate CSS modules with TypeScript or something. That kind of problem simply doesn't exist in autotools world.
You're not totally wrong; I'm getting into that age range.
It's not that I prefer those tools; they are really obtuse. It's just that I can't handle the moving target of JavaScript. I'm sure I can figure out esbuild just fine, but in a year or two it could be abandoned in favor of swc or Vite or a Vite-esbuild-swc uber package.
I don't learn any transferable skills writing Webpack or Babel config. They don't even necessarily transfer to the next generation of the same tool.
I would also take a stable autotools over an unstable autotools, and I consider most of JS-land roughly equal in usability to unstable autotools. Autotools was also not that bad on the happy path where you were targeting, say, the top five POSIX systems over ten years - and maybe you didn't even need it at all, if you didn't need the performance from distinguishing each platform's best supported fd polling variant. Vs. JS, which is still bad even if you're only targeting evergreen browsers, because maybe you're stuck trying to integrate CSS modules with TypeScript or something. That kind of problem simply doesn't exist in autotools world.