The catch is that using NPM and CommonJS modules for front end packages makes it so that tools like Rollup and the Closure compiler can't do the kinds of optimizations they are capable of. The code we ship is doing a lot of runtime dependency resolution that could be done at compile time if we constructed our modules properly.
I think that many of the front end tools we use now result in an optimized developer workflow, but usually not optimized code.
I think that many of the front end tools we use now result in an optimized developer workflow, but usually not optimized code.