I think that when you delve into studying NPD you will begin to recognize there are several different variables that can contribute to the behaviors that can fit into what is deemed NPD.

There are individuals with NPD that were traumatized and often abandoned in childhood, but there are children that struggled with learning disabilities and struggled to learn not understanding "why" and grew to find ways to self protect that are simply not their fault, but instead these individuals found ways to compensate for having low self esteem because of this learning challenge. However, children can also be raised by a parent to believe they "are" the center of the universe too, so this kind of upbringing is very different than being abandoned or neglected or traumatized.

Children see themsleves as the center of the universe for several years, if a child is not guided in developing empathy, that child can have that deficit right into and throughout adulthood. Children can have a difficult time thinking about how others feel, but simply see the world according to how "they" feel and what "their" needs are and begin to see others around them as a threat to having "their" needs met. Often their desire to be adored, or what is often called narcissistic feed, is connected to "lack of" in their youth that is something they try to make up for all their lives "unknowingly". This is part of the reason behind, "Narcissists do not know they are Narcissists".