Producing information is costly. There is a market for it but no general magic solution (this applies to both govt and companies, but I guess it's easier to look into a bunch of small companies rather than one huge govt).
Corporations are accountable of the wrong they do to third parties. It's the whole point of having a judicial system.
How do you control a govt ? By rioting and voting every 4 years ? Here's how it can work for companies : http://www.econlib.org/library/Enc/MarketforCorporateControl...
Sure but less of a mystery than how we can make corporations transparent, accountable and openly documented.