Since when has supreme powers been enough to have one obtain godhood? Man, standards are slipping everywhere. In my day, any god that couldn't do the whole "created the heavens and the earth" thing wouldn't even be noticed. I bet it's that stupid Prometheus's fault. He gives mankind the secret of Fire (Prometheus really brought a mastered Fire Materia down from Olympus), and the next thing you know, the mortals down there are figuring out how all Materia works, and they start throwing lightning bolts around and thinking they're "gods" just 'cause they can kill all their neighbors.

Seriously, you're not a god just because you're more powerful than everyone around you. Or even if you're more powerful than everyone else on the planet. Put together. Being a god requires far more than just power.