It’s already a reality, I was doing it about ten years ago.
require.js was a big piece of the puzzle, allowing the use of modules in browser without a build step.
The only time a “build” happened was to concat/minify scripts for production release, but even this wasn’t strictly necessary.
There were other pieces involved, but we had a powerful stack (aforementioned modules, css preprocessing, reactive templating) that had a faster and easier workflow than anything happening today.
require.js was a big piece of the puzzle, allowing the use of modules in browser without a build step.
The only time a “build” happened was to concat/minify scripts for production release, but even this wasn’t strictly necessary.
There were other pieces involved, but we had a powerful stack (aforementioned modules, css preprocessing, reactive templating) that had a faster and easier workflow than anything happening today.