At the end of the day, if something is economical, it basically happens automatically in a market economy. For example: It would be pointless if the U.S. government started running car rental stores in every major population center... because -- duh -- that idea makes money and other people are already doing it.

From that perspective, you could argue that it's actually the government's job specifically to do uneconomical things. That's why running a government is hard; almost all ideas are uneconomical, so how does one manage to pick only the good uneconomical ideas? Good government policy requires the kind of foresight that can't be gleaned from a cost/benefit analysis.