Profitable because 'Rat-infested town govts, 'Rat-infested city govts, 'Rat-infested state govts, and 'Rat-infested national govt are typically buying cars from Government Motors.
[I call it the "national" govt because it likes to "nationalize" whole industries]
Go the Zero Hedge the other day.
GM is "Stuffing the Pipe" Again...
http://www.zerohedge.com/news/2012-12-03/gm-channel-stuffing-wtf