Since most of the stuff is based on their own terms, like insider info, or something else thats off the books.
A normal trader going into the market using a thinkorswim account will get killed, not having a edge.
Insider trading is not the norm.
People do get prosecuted and go to jail for insider trading - think of Raj Rajaratnam and Rajat Gupta.
It is just not worth it for people in important positions to make use of insider information.
Stock market were manipulated by a whales since the beginning, and no control commission for securities will gonna cut these dealings.