That is true. The power balance would shift. And perhaps the idol spies that work for Asmodeus would even be able to watch and report on the events that unfold so that we wouldn't be totally in the dark.

But consider for a moment if what we heard is true - and yes, I know you doubt most things but hear me out. In Asmodeus's realm, it was stated that only Pythia and Asmodeus cared about this production and dealing with humans.

What if removing Asmodeus brings someone even less palatable around? Or even worse, means the end of the production? It's the first run. A test. They don't have to keep it going.