Workspaces has existed in linux for a very long time. I'm guessing late 1980's based on this article (They say X Window System implemented virtual desktops in 1989, and the first to use the X Window System was linux).
A problem arises with unlimited workspaces though - that they can become disorganized fairly quickly. Your first workspace can be dedicated to working on an article, a few google searches later, and you now have cat videos and how-to articles on training them for world domination starting with fetching your slippers.
I'm calling it now - within the decade (don't know how slow windows is going to be) windows and apple will release "Managed Workspaces" where you can assign specific programs to different workspaces.
Meanwhile.... its already done in linux.