"Creativity is, in a nutshell, a bit crazy - and most crazy people are too disorganized to do much. But geniuses require to be a bit crazy, yet also do prolonged focused work - and this is a reason why there are so few of them.
So - high intelligence is very rare (and some societies have too low an average intelligence to generate more than a tiny proportion of very intelligent people).
Within this tiny group of highly intelligent people, on top of all this, to get the coincidence of a creative way of thinking with a sufficiently persevering personality type is very rare.
And among this small percentage of a small percentage, there are the workings of sheer luck, there is the higher than normal risk of (self) sabotage by mental illness and addiction, there are the problems of a higher than usual probability of an abrasive or antisocial personality - and (as Murray identifies) the likelihood that for a person to aim very high requires a belief in transcendental values (the beautiful, the truth, virtue) - and that some societies (such as our own) lack this belief.
Put all these together and it is clear why in all societies genius is rare; and why genius is completely absent from most societies."
- Bruce Charlton, Why Genius Is So Rare