Setting Up a Dev Environment With Webpack 3

I have observed that some people still write the ancient ES5 syntax of JavaScript, and it’s disheartening. I wonder what keeps them from moving forward. Some must be driven by psychological inertia, but some likely just find it too complex to make their new syntax run in a wide range of browsers.
In fact, nowadays, we don’t have to fear it anymore. One can set up a dev environment where tools decide what transformations the code needs and what polyfills to load depending on the selected target (list of user agents to support). The only thing those people need to start “a new life” is a proper setup.