Would it be too hard to replicate the style for the printed page? Or is it probably because Trey Parker from all accounts, is a massive control freak? In other words, he'd probably want to be involved as like the head writer too. Plus, and he is known to change his mind on what is going to be on the next South Park pretty much all the way up to air. And you can't do that in a comic book form. You can flip some story beats but you can't just change everything on a whim.