More recently much the same sentiment has been expressed about Microsoft.
However that perception now appears to be under challenge.
ReadWriteWeb reports in its article Google Sues US Government Agency Over Using Microsoft Only that,
Google has filed a lawsuit against the U.S. Department of the Interior for requiring that messaging technologies must be part of the Microsoft Business Productivity Online Suite in order to be considered for procurement.
Apparently the case has some merit (the article goes on to say). While the Department had justified a Microsoft preference due to 'enhanced security', Google Apps were recently the first cloud service certified by the US Federal government's Federal Information Security Management Act certification.
This case, if successful, might see other software makers challenging US government requirements for vendor-specific solutions. Internationally it could even, over time, help open source and cloud application developers gain greater consideration in government procurement processes.