Adjusted for inflation, cash compensation for line workers has actually decreased over the past few decades, and even when you include healthcare compensation it's grown only about 30% or so. In contrast, executive compensation over the same period has more than quadrupled.
Do they deserve this? Almost certainly not. There's simply no good reason that a CEO of 2011 is worth 4x more than a CEO of 1970. The reason their pay has gone up is simple: for all practical purposes, CEOs set each others' pay. And they keep raising each others' pay because they can. It's a pretty nice racket.