This is everything-you-thought-you-knew-is-wrong kind of stuff. In an HTTP/2 world, there are few benefits to concatenating a bunch of JS files together, and in many cases the practice will be actively harmful. Domain sharding becomes an anti-pattern. Throwing a bunch of <script> tags in your HTML is suddenly not a laughably terrible idea. Inlining of resources is a thing of the past. Browser caching — and cache busting — can occur on a per-module basis.
I can't help but think that web development might actually make sense some day.