The human being, having an extended period of upbringing and education, is dependent upon its parents and its educators for many years. It is helped by the community to be a productive member of society, to be able to add value to others, so that it is in turn paid money or goods for its own survival.
One is helped to stand up, then one helps the next generation stand up, and so on.
This cycle can only succeed on the basis of something which complements an individual's selfish desire to survive. Namely: Altruism.
One is helped by one's parents in a combination of selfishness and altruism. The parents are selfish because it is their child, carrying their genes, but they are unambiguously altruistic in that their own pleasures take a back-seat to the child's.
Similarly, the community is a combination of selfishness (in that it regards the other communities as threatening) and altruism (in that it is willing to carry its weakest).
This is a precarious balance, and any community or individual which becomes too selfish or too altruistic does not last very long.
This double-standard, one for "one's own" and another for "the rest" is essential for the health and well-being of an individual or community.
The evolution of society, just like genetic evolution, happens when a change/mutation enhances the overall fitness. But unlike genes, social evolution can also be brought about consciously. That is the inevitable complexity of "progress". Society exists to propagate itself, and hence is resistant to change, even beneficial change.
The societies which evolve quickly, and are fitter, are those in which the cost of being different is not fatal. In those societies, ideas have a healthy ground on which to compete with each other, unlike primitive societies, in which difference in opinion is considered a blasphemy, sin or immorality.
However, it is obvious that a disregard or disdain for tradition can too easily become counter-productive. It is nobody's case that all change is good change, or that all tradition is bad. The quandary of modern societies is its desire to let individuals make their own life choices, but its wish for them to make "good" life choices.
An individual is a carrier of genes and traditions, to be passed on to the next carrier. An individual's life is of little consequence, compared to the life of genes and traditions. But that "little" consequence is not nil.
An average human being is important in a limited way, to a very small set of people, and an exceptional individual may, rarely, question a tradition in a way that echoes with others. The impact on a tradition of that questioning therefore depends upon whether the rest of the society is somewhat tired of that tradition as well. And it is worth considering that historically, many people came up with similar ideas at about the same time. The time was ripe.
To come to terms with suffering and mortality is therefore to accept that others, especially the next generation, may be more important than oneself. That one is a small part of a teeming species, a single member of a large community, a single carrier of ideas and genes which exist in others as well.
A narcissist cannot do that, and hence he struggles more than others against what he perceives as "needless" pain. The stress of inter-personal relationships, the depression of growing old and irrelevant, the resentment towards others' expectations, the demands of child-rearing are more acute in a narcissist, and he seeks solutions in which his fulfillment is unrelated to others' states. Where a parent might find some kind of fulfillment in seeing its children happy, or a scientist might find some kind of fulfillment in seeing a medicine save lives, a narcissist regards these fulfillment as conditional on others, and hence unsatisfactory. The only fulfillment worth its name to him is autonomous fulfillment.
Life as a whole may not matter much. But individuals matter even less than that.
In other words, it may all end one day. But you will definitely end sooner than that.
The end of narcissism is to start to live in a way in which your own happiness is not the foremost goal of your life.