No, and that’s the whole point. God’s power is never limited. God exists on a higher plane than everything, sees longer and farther than anyone else, and can always find a new way if His plans don’t work out the way He wanted to. The reason God’s plans don’t work out the way He wants them to is because God pretty much never gets His hands dirty, He always goes through us, God’s plans fail because we fail. If God has to step in, then He’s either teaching us a lesson or things are well and truly fucked.
Mythology doesn’t work otherwise. How can you tell a story in which one of the characters of the story can just wave his hand and remove all the drama and tension? Now that I think about it, Greek mythology never pitted gods directly against each other either. It was impossible and rather silly to say that, say Poseidon was more directly powerful than Ares or Hera. They might get one up on each other from time to time, but it wasn’t until modern times when people really started to want their deities to have legible power levels.
God would never lower Himself to confront a demon personally. He’s got angels for that. But He’d only send in the angels if we can’t get it done. And even then only if there’s a really good reason to want to protect whatever it is the demons are after. If God didn’t let the demons win from time to time, then there wouldn’t be any point in having them around. And of course He wants demons around, what would we fight if they didn’t exist?