The reason, according to John K.:
"I was trying to explain to the ABC executives exactly the system that we used on Ren & Stimpy, and it was too radical for them. We wanted to do the cartoons the way Bob Clampett did the cartoons, and that was to write outlines and then do a storyboard, which the storyboard artist would flesh out. The Clampetts were willing to go with that, if I remember correctly, because Sody [Clampett] worked on the original Beanie and Cecils with Bob, and she knew that the system works. That's how all the great cartoons are made.
"But I was in the position of having to educate everybody who didn't know anything about the history of animation."
"ABC hired their own story editor, who had no loyalty to us, no loyalty to the Clampetts, no loyalty to the history of animation, didn't like the artists, and proceeded to write the worst scripts in history. We were stuck with them. As a compromise, I said, 'You've got to at least let us draw these funny.'"
"We had no control over anything."
