I don't get this, and never have. If there are powerful demons, devils, dragons, humanoids, humans, goblinoids, Yuan-ti....whatever, who keeps them all in check if there aren't powerful NPCs?
Are the 4-6 people in your group the only ones that ever level up? How is that a living, interesting to role play in, world?
I've never understood the argument that there are too many NPCs in the FR, if anything, I don't get how there aren't more, in FR and all the published worlds.
In a city with tens of thousands, wouldn't there be many, many that are more powerful than the PCs (at least at levels 7 and under)?