That hasn't been my experience. Depends on the caching mechanism used I guess, but if you bake cache busting directly into the URI like I do (i.e. there's a has

That hasn't been my experience. Depends on the caching mechanism used I guess, but if you bake cache busting directly into the URI like I do (i.e. there's a hash digest in the path), the browser doesn't need to make any additional network round trips for any nested imports that have already been fetched - they are all 0ms cache hits. And even if you use a cache mechanism that requires reaching out to the server every time, it's still very lightweight (you'll just get a 304 not modified for any nested imports) Even if vanilla modules is slightly less optimal than a bundler performance wise, I would still argue the additional complexity (for learning, maintaining, deploying, debugging) introduced by said bundler is not worth the extra cost for most websites.