Why I can't get rid of the vuetify from my bundle?

I'm trying to reduce my vuetify application bundle size by using CDN and webpack externals.

My configration of vue.config.js is as follow:

module.exports = {
  "transpileDependencies": [
    "vuetify"
  ],
  chainWebpack: (config) => {
    config.externals({
      firebase: 'firebase',
      'firebase/auth': 'firebase',
      firebaseui: 'firebaseui',
      vue: 'Vue',
      vuetify: 'Vuetify',
      'vuetify/lib': 'Vuetify',
    })
  }
}

But, Vuetify/lib is still remained as follow:

Ah, I've exhausted the effort of googling…

Do you have any idea? Any pointing, suggestion and opinion is so welcome! Thank you!