We're not missing anything, or at least not anything I actually miss. I had a previous supervisor who chided me for "not using an IDE" because I was using Emacs -- Emacs! -- and insisted I should use something more featureful.

First, that doesn't exist, and the notion's laughable.

Second, I have every feature I actually want to use in Emacs (and Zed and even *vim), and have no reason to believe that any random bullet point someone might come up with 1) doesn't exist in those editors, or 2) that I'd use it anyway.