I've had to write simple plugins for both SublimeText and VSCode to get the equivalent of a one-liner in Emacs. Comparing anything with Emacs extensibility is not even fair. There are hooks for everything, you can invoke other people packages from your own code, if you want trouble you can overwrite other people's packages specific functions, etc.

Emacs has a lot of flaws though. I don't really recommend people using it. Even after showing the neat stuff, I can do with it.