Well, yes. That's what makes Unix OSes so great. Programs all the way down to the command line are separate from the OS. Modules and drivers are also semantically separate from the core.
sudo aptitude purge emacs
sudo apt-get install vim gvim
gvim
Edit: Clearly I'm joking. If you wanted a serious answer, Emacs is just a large, easily extensible program. It's not really an OS. That's like saying Google Chrome (contains a package manager, web browser, text editor, scripting language, and much more) is an OS.