[pessimizer]

>By virtue of Red Hat. If Red Hat goes away, I'd be surprised if they can keep up that commitment.

Why would Red Hat be going away?

>Now try Office 2013. Last time I tried, not even CrossOver could run new Office versions without serious loss of functionality.

Libreoffice exists, and is very adequate for a government agencies' typesetting needs.

>Windows 7 is very similar to Windows XP.

Windows 7 is also an old product that is being phased out in favor of 8 and 8.1.

>The same can't be said for e.g. GNOME 2 -> Unity or GNOME 2 -> GNOME 3.

What about GNOME 2 -> MATE or GNOME 2 -> Cinnamon?