Re: That is quite a question!
As I see it, an a**hole is just a reckless, careless, selfish jock that wants to throw their weight around, but a narcisistic person is a cold, calculating, scheme inventing, self-enthralled, coward,...scared of who they really are, scared of having to face their conscience and constantly pursuing ways to ignore it and feeling a constant, feverish need not to address reality for that reason (they NEED to always be unreasonable). They will tend to TALK FAST (lest they STOP and see REAL reality, because if they see REAL reality, their conscience is waiting for them). They're not just scared of realizing who they really are, they're scared that other people are like that too (that's why they mistrust, especially those who are actually being nice to them, they think it's a CON scheme). They can't see outside themselves, they consider the world to be full of prey (they are PREDATORS). It just might be possible for a young undeveloped narcissist to change (that's a big MIGHT).
When you said...
"They reacted very strongly, taking extreme stands, trying to overwhelm their tormenters"
This is because they reacted with BITTERNESS and schemed against the world for vengeance (they decided to inflict their pain on others) instead of just ENDURING their plight justly as an unfortunate situation of their own.
They do NEED to always imagine themselves smarter than everybody (especially people who they FEEL are a direct threat to their "top dog" status. If they sense your lack of insecurities and your contented self-sufficiency, they'll be on your case for a "showdown".
When you said,...
"like for more than sixty years"
I thought my family members would grow out of it also, but NO, it is a self-sustaining, perpetual way of life (truly amazing). It seems that the difference in childhood is that,...if you react JUSTLY to your bad situation and simply ABSORB the pain and consequences, then you can become BETTER (heal), but they reacted by becoming BITTER against the world and UNJUSTLY chose to inflict their pain on others, so, as much as I am tempted to feel sorry for them, I have to remember that they decided to be UNJUST (I'm still tempted anyway).
What I was saying about "playing dumb",...
They make a habit out of replying "What do you mean?" to anything you say that is completely self-explanatory in a personal conversation (they are covertly picking your brain to either construct a scheme or simply find out what they can get out of you, there are NO innocent questions, it's amazing, how do they not burn themselves out?). Otherwise, they are SMART/cunning, but "playing dumb" is a ruse.