Granted I'm sure SOMEBODY somewhere has gotten fired for choosing Microsoft, but from my perspective one of the big problems in government (where I work) is that there is almost ZERO risk to choosing whatever MS happens to sell, even if it's horrible.
If you stick your neck out and choose something like Google Apps and it goes south all the fingers point at you. If on the other hand you choose Office 365 and things don't work out you can EASILY just point the finger at Microsoft and say "It's Microsoft and Windows, not my fault).