Windows can be served to GNU/Linux desktops in a number of ways besides dual boot, Wine or desktop virtualization. A zero effort method is to use Windows terminal services and a client like Gnome’s, “Terminal Server Client”. This is insecure but no more so than having Windows on your network in the first place and it works well. With a little more work, Windows can be virtualized and served out the same way to desktops from a server. This greatly reduces the work of keeping Windows around by making the whole system a file. With a little more work, things can be served through OpenSSH for privacy and security either as Windows terminal services or an X11 forward. Any of these takes care of the edge cases where an irreplaceable vendor has made the Windows only mistake. The vast majority of business desktops don’t need Windows at all.