All you do is buy a Mac, then install rvm because the version is wrong, plus use bundler because global state is a terrible idea for gem dependencies, and you need to have the right bit of Xcode Command Line Tools going to compiler native gems, and if you’re head by one version you get compiler errors, and...
A few years pass, and the act of changing anything in the application will require working around bugs in an old transpiler that can't be updated because of mysterious bugs that some code relies on, configuring dependencies in an obscure package system, converting HTML into a UI layer that's a complete mismatch for the application's present design, and converting "new" calls manually into some upside-down system that is there only because of novelty value years ago.
Now your javascript is full application code, it needs to communicate with multiple other services and handle complex Material Design UX across multiple popular browsers, devices and screen formats.
Though I definitely agree that people are going nuts. Needing to npm/bower install and then running gulp to process SASS and CoffeeScript (NEVER!) just to deploy a brochure site is unnecessary.
I'm skeptical that some folks are actually mastering all of the tools they're using right now. And if they are, how are they still finding time to work on the their own application?
I'm still learning these tools as they pop up, but only so that I know what I'm opting out of when I keep them out of my projects. :-)
In the course of a few weeks, I've experimented with react + coffeescript, react + typescript and settled on react + jsx + flummox + react-router in es6. I've finally come to the realization that I need to read the code for all of these to have some sense of what is actually happening. Not doing so is leading to obscure bugs that take hours to chase down.