The world wouldn't be perfect if each State (and the federal government) had a publicly owned bank, but it sure will be better. The Fed, which is a private bank tasked by our co-opted government with conducting monetary policy, has refused to lend to the States. This is the cause of the budgetary problems and resulting austerity measures and structural adjustments. If each State had its own bank, it could borrow from it, and it would be a source of income.
If I haven't convinced you yet consider this: The RNC, the Tea Party, and the US Chamber of Commerce oppose the idea saying it is "big government," "socialism," etc.
http://www.opednews.com/articles/Feds-To-States--Drop-Dead-by-Ellen-Brown-110518-79.html