I've heard of rare cases where psychopaths are self-aware. They might never feel real empathy, but they can lead a functional and rewarding life (they just might view moral and relationship decisions as mathematical transactions rather than emotional ones). For example, "I know it is unacceptable to do this, even though I see no problem with it, but I'm going to avoid it as part of adhering to my social contract."

I don't think that narcissists are capable of this kind of self-awareness or control, at least not when they have narcissistic supply. It is a truly sad reality.

Personally, I think narcissists because of the sheer chaos they cause in their environments. Even one narcissist can destroy a community culture.

Of course, I am no therapist and I don't have solid sources on this. These are just my thoughts based on what I've read here and there.