Narcissists deserve pity. They develop an idea of being an exception in some way. Some way in which what applies to others doesn't apply to them. You need to make them feel safe under the same rules.
Concerning yourself with narcissists means that you wish to determine persistent qualities as explanations for bad people. The intimation that they cannot improve is linked to that desire to assign enduring traits to explain opportunistic behaviors.
They may, for example, have a role model. Someone that wouldn't be scared of what they are scared of. A kid that gets bullied may want to be like Rambo.
They may try to emulate that example until it becomes more painful to doubt that they have succeeded than to admit it is better to be themselves. So then they will reject whatever conflicts with this dreamed up, safe self image. It's a defense mechanism.
Healthy people are able to process things at their leisure.
Some people instead rely on a sort of system of rules for what to expect. Because structure is necessary for comfort.
So they act tough like Rambo. Someone doesn't seem impressed. They feel narcissistic injury because their survival mechanic is failing. Then you perceive what appears to be ego. They enter fight or flight mode.
Rational arguments become harder to prioritize and etc
