If you don't need backwards compatibility, you can use ES6 modules directly in the browser [1] and even load NPM packages in module format from Pika or Unpkg.

Living without a bundler was alright.

At my last job we checked Google Analytics and almost 100% of our users were on greenfield browsers, so we moved to that and had no issues.

[1] https://www.sitepoint.com/using-es-modules/