Once again, that's the whole Nintendo won't allow the good guys to die thing. If you'd have given Earthbound to some other company, there'd be one change for sure, they'd definetly have to have died in order to stop Giygas.
Or you just pit Giygas against an athiest. They'd never stand a chance. I don't know too many villains that actually praise the heavens. Another reason why Giygas could do well in an all villains battle.
Poll