I was just reading "Predictably Irrational" where he speculates that it's because in the early 90's, public companies were forced to make executive compensation

I was just reading "Predictably Irrational" where he speculates that it's because in the early 90's, public companies were forced to make executive compensation public, so executives suddenly knew what others were making and that gave them a huge lever in negotiations. He draws a correlation between the creation of the rule and the sudden rise in executive compensation in the early 90's. Is correlation causation in this case? Seems like it's worth exploring. I don't know how boards get away with the gigantic exit packages though, except that it's probably because all these C-level execs sit on each others' boards. As for career-ending, how does this explain things like Robert Nardelli? Personally, the only thing I see ending an exec's career is prison.