I completely understand this reasoning for smaller companies, but a company like Spotify will care deeply about the dependencies in their project. Just because

I completely understand this reasoning for smaller companies, but a company like Spotify will care deeply about the dependencies in their project. Just because core-js is a dependency of a dependency simply doesn't matter and if anything, makes it even more essential. Unless they're extremely incompetent, any 3rd party code that's to be deployed to their entire user base is presumably being reviewed in detail. And I guess I'm not even sure I buy the argument that most developers don't know about core-js. I know I'd be extremely concerned if I was hiring an experienced frontend dev who didn't know what core-js was. Anyone who's thought about browser capability before should have had to think about polyfills, and naturally their use of core-js. It also comes up a lot when trying to optimise bundle size given the size of core-js.