Well, he wasn’t really banished, he ran away out of guilt because he thought his friends hated him and didn’t want him in Bikini Bottom anymore.

Yes He Was! SquarePants was out of a Job & Outta 12 Bikini Bottomites Hair. In WhoBob WhatPants.

No wonder why the bottomnites went on a rampage after SpongeBob left, they notice SpongeBob was gone missing.

No The Reason is Bikini Bottom has now gotten Relaxed & Boring without SquarePants!