what a great episode, and a great discussion y'all!
I personally believe that God did the reset, but you have to understand modern storytelling of clashes with the Devil. They usually take place in a dreamlike or otherworldly place, or outside known time and with common situations.
The Devil DOES have a lot of power, but He's more apt to use it as a display than God does. God is more subtle, wanting His children to grow strong by challenges of faith, yet is there when you call for him. The Serpent is quick to challenge as well, and is a Known Trickster! He can quote Scripture with more skill than even the most holiest of men and women. Even those Blessed by God often find themselves lost in challenges of the Devil at first. He's THAT powerful.
But the power is an illusion... ONCE steadfastedly stood up with God as your shield, the Devil quickly retreats, blinded by God's Brilliance.
Now in this fictional story, the Devil usurped God's power temporarily. But only so. This whole story took place in the blink of God's eyes... hence the reset. Sam could well have met his match, but once the Devil revealed Himself as that weak, he was able to be beaten.
As is usually the case. Both in fictional, and in factual stories.
Ahhhh, enough of my rambling. Ya caught me with a philisophical moment!