There's always a loophole that allows SpongeBob to escape from whatever plot Squidward tries to set on SpongeBob even if he does try to pull some legal sleight of hand. And it would be no fun to see Squidward happy except if it's for one episode. We've also seen that if Squidward does try to live his life without them, he hates it from "Squidville".

Squidward's character was made that way and if they change his attitude, then there is bound to be more complaints about why he's so happy now or why SpongeBob and Patrick haven't bothered him. The complaints ought to be much more than the complaints about Sandy's scientific side of her in Season 4 and after.