Nothing is perfect and never will be. We can fix some problems, but we can't fix 'em all. Markets have deficiencies that can be corrected only by government action. Government flaws, though, are prone to prevent corrective actions and even worsen the economic condition. No one knows everything.
Information is a scarce commodity.
Acquiring information, like producing any good, entails the opportunity cost of limited resources. Those with more resources can secure more information. Sellers, who have a good, usually have more relevant information than the buyers who want it. There's more than meets the eye. Every action has many effects, some intended and obvious, others unintended and more subtle.