I'm a long term emacs user and I know that my emacs use is not down simply to lock-in. I know this because a year ago I spent a month using Panic Nova to see what I might be missing with emacs.
Nova looked super pretty and it's easy to figure out how to do a lot of things out-of-the-box that's harder to figure out on emacs at first.
But there are a couple of core things about emacs that I just don't see replicated in the popular IDEs.
1. The way you manage buffers and "windows" (just partitions of the screen in your GUI window). Buffers and windows are decoupled, which will make no sense to most people if they aren't fluent in it. And these little window partitions are quickly built, re-sized, split, and destroyed at a moment's notice from the keyboard. I can and do regularly go from 1 to 12 partitions at a moment's notice. I switch buffers in partitions constantly.
I tried so hard to figure out how to not make buffer and window management suck in Nova, but to no avail. I've also done some professional development in VS Code, and it doesn't appear to be any more flexible.
Maybe someone has an extension, but I doubt it. And this is too core to my development experience to trust to something as ephemeral as an extension. And emacs has already been doing it for 30 years.
2. I use emacs in the terminal, whether on my desktop or ssh'd into AWS.
The development experience is 100% seamless. Being able to work remotely on any server with my exact same developer experience is huge for me. I don't have to have a mirror copy of the files and do any syncing between edits. I can use all the project management, file browsing, and directory searching features built into emacs with no problem. I'm always at home.
The last thing I'll mention is that, contrary to the person having doubts in the linked article, I'm not an emacs power user. Currently I use an almost-stock spacemacs install, not even in evil-mode, and I've barely explored it. The basic emacs features I learned in the first couple months of using emacs give me more than anything I've found.
I will say that if I made a whole career out of Java or .Net development, and if versatility wasn't that important, an IDE tailored to those environments would have some polish that's hard to ignore. But if I knew I was missing the foregoing, it would hurt a lot every day.