I agree, Lumb, Scamtini, and Lowenthal should all be in prison.
However, the SEC is full of "big game hunters." Taking out a serial $2 million fraudsters doesn't get your name in the papers. And more important: a lot of SEC attorneys have their eyes on their next job. Taking out dozen of scamming guppies like Lumb is God's work, and that is where the reward will come. Taking out a $500 million scammer, preferably with a famous name and ancestry that goes back to the Mayflower, is how you get a job at Skadden Arps or a shot at being elected to your state's Attorney General position.