Yup the whole thing about Pennywise is that he's essentially an eldritch horror from beyond who is designed to destroy worlds that got lazy as shit and decided to shirk his duties by making a corporeal form and just setting up shop in a small town and feasting on it's children every few decades.

As bad as Derry was, the rest of the universe kinda got good deal with IT deciding to confine itself to Derry until the Losers wiped IT out.