Well...
...if it is going to destroy everything, change the UI to such a degree that your staff require retraining, demand massive investment in new hardware, break programs and generally cost a lot of money for untold grief; perhaps people should look at a Linux distro, even for a few minutes?
It will still require re-training (but you could customise the hell out of Gnome/KDE/XCFS and keep that to a minimum), many programs have OpenSource equivalents (e.g. MS Office vs OpenOffice) and even if you *MUST* have the Windows prog (as does happen in the corporate world), it can hopefully run under WINE.
Big pluses would be the saved license fees (which should more than offset any config costs), less virus attacks, better security in general. And you can still buy proper support if you want/need it.
Not practical for everyone I absolutely agree, but not an option that should be dismissed out of hand either.
Of course, people will most likely just unthinkingly follow the Redmond diktat.