I think the real issue is that their costs to animate have to be pretty high. They use traditional animation techniques that are outsourced to South Korea. SK is not a low-income nation by any stretch of the imagination, and each episode takes months to produce... Versus a show like South Park which takes literally days.
Changing animation techniques would likely have a much larger impact on the bottom line than taking away money from the actors who are the huge driving force behind the show.
Back from the dead, I'm afraid.