Okay, having worked in the film business, I will put in my two cents. According to SAG (Screen Actors Guild) the average actor makes about $8,000.00 a year. That average includes people like Tom Cruise and Brad Pitt. Most actors don't make huge piles of money.
The studio execs make the huge money in the business, because they resell these films and tv shows over and over again. They make the money, while the people who made the movie are, in a lot of cases, broke. The actors, like the writers and everyone else in the world want there fair share. The studio could not make these films without them. Hell, residual checks is how most actors pay the bills.
It's like this, say I ask you to make me a custom sculpt. With this sculpt I make a figures and sell them for a lot of money. Shouldn't you be paid for more thatn just the one sculpt?