Isn't it like the movies? The huge salaries are part of what draws people in. And NO ONE in the audience has ever said: "Well, I would have preferred Brando or DeNiro in that role, but they're too expensive, so let's see what the kid just out of CalArts can do."
The entertainment business is not run on the same principles that apply to other businesses. Look at the cash Dan Snyder gets for being a total creep while running his organization into the ground.