Multiplayer is a SAAS term for collaborative. So in the same way google docs is collaborative, I guess the OS would be too?
It's probably every industry that has this sort of nonsense.
Collaborative is a very overloaded term, it's everything from Git to Google Docs to screen sharing to multiple people accessing one app at the same time via remote access. Multiplayer is a term that usually refers to a very specific mode of collaboration, where multiple people can work on one project, on their own computers, with their own cursors, at the same time, with all changes instantly synchronized between participants.
Google Docs is both collaborative and multiplayer. Git is definitely collaborative, but not multiplayer, same goes for sending patches over mailing lists..
Google docs is a realtime collaborative word processor. Git is a collaborative source control system. If you told me that Multi is a realtime collaborative editor then I'd instantly understand. But trying to say that my OS needs to be multiplayer is just confusing buzzword bingo.