They can't even go back to making classic south park episodes because Hollywood has destroyed its cultural impact in the meantime so there's nothing to riff on. All anyone knows about Hollywood now is race/gender swap reboots. Even the "new" movies are just "what if Better Call Saul was a Spy" "What if this guy couldn't feel pain and his best friend secretly a fat asian guy" "What if a teen girl had depression", and nobody saw any of them.