NPM + Github + Node.js + JavaScript is easier + JavaScript was already front-end ubiquitous came together in a perfect storm to allow JavaScript packages to be created and spread like butter on toast. JavaScript is the easiest to develop with, has the most adoption, runs client/server and has the easiest package manager to both publish and use. Why is this even a question? This is not an argument for JavaScript but merely stating why it is changing so fast.
