Yes, but if I own a company, and Gitlab does something that we don't like to our project, I could conceivably run my own on a Digital Ocean droplet or AWS or Azure or something, so that my developers don't have to radically change the way they work.
Granted, Github has Enterprise, but that's proprietary, and I like that there's no need to worry about license fees and whatnot with Gitlab.
Wouldn't every single user have to create a new account in the Gitlab instance running on the new server?