The demon's problem is that, by Not incarnating and having separated themselves from God's direct presence in Heaven, they are not-easily brought-to-a-point...
They are eternal and indestructible spirits who have taken the side against Creation; and as such they are Not-very-good at learning from experience.
Perhaps, the hellish economy works more by a kind of 'natural selection' among demons, rather than by the learning and development of individual demons.
That is, maybe the individual demons stay much the same (because they don't learn from experience), but one or another comes to the fore at different times and places and situations; for which they happen to be best adapted.
Some rise, some fall back down the hierarchy; and the supreme Leader varies at different times, and perhaps too in different places - hence the several names for the chief demon in different sources and cultures.
So The Devil may be sometimes the passionate and charismatic Lucifer, sometimes the coldly bureaucratic Ahriman, sometimes the sadistic Sorath - whatever is working most effectively here-and-now in the work of opposition to God, Good and Creation?
