With the exception of Active Directory (for authentication) and File/Print services, the number of Linux servers FAR outweighs the number of our Windows Servers. So "already there" in the Server space.
Desktops will be an entirely different matter since that is what users actually TOUCH and USE to be productive.
Active Directory and File/Print, are just a couple, but Munich had a lot more issues, including trying to use the FOSS Libre Office, which had many incompatibilities with file formats. There were other issues, and perhaps your company doesn’t have the same kind of issues as Munich had.