"It's because Godspell is cheaper to mount."
not really, with both shows, directors' interpretation is so important. Both shows can be done very minimalistic, and you don't have to have a lot of actors for either, depending on the vision. I saw a production of Godspell last year at the Walnut that was heavily reliant on the set and special effects. It probably cost a pretty penny.
I find that Pippin is done best when done minimally.
"I'm an American, Damnit!!! And if it's three things I don't believe in, it's quitting and math."