[Note: the following is a non-scientific theory - in that it assumes the reality of gods and spirits and that humans can receive communications from them; whereas science excludes the reality of gods and spirits. Strictly, science does not assert that gods and spirits are unreal; but rather that they are not part of science, are excluded from science a priori, as a basic assumption. In other words what follows is not-science; but of course it is not anti-science, nor unscientific; nor is it against the scientific interpretations - the following idea is outwith science.]
Creativity is 'inspiration' (a breathing in of spirit) - which is a sensitivity to external knowledge about reality.
Therefore, creativity is in opposition to conscientiousness and empathy - because they entail being mostly interested by, and doing, what other people want, being mostly interested by and feeling what other people feel.
Creativity has a negative correlation with conscientiousness and empathy - since they are the hallmark of a person who is sensitive and orientated towards to human communications.
Creativity is something different.
Creative people must of necessity have their focus turned away from the social world - at least while they are being creative.
Away from the social world but therefore towards what? Towards the unseen world; the supernatural world, the world of non-human intelligences; in other word; the world of gods and spirits, souls, angels, demons, God Himself.
That is the source of creativity.
And that is the reason why creativity is an insight into reality.
(Even evil creativity is an insight into reality - because typically it first knows reality, and only then distorts or inverts reality.)
Because of creative persons, humanity has access to extra-human knowledge or ability as applied to human problems or needs.
Creativity is a direct route to something beyond human ability.
Creativity is not random - it is directed - it is directed towards reality.
So, why should creativity be associated with altered states of consciousness: trances, dreams, insanity, intoxication?
Well, such altered states of consciousness always have been associated with communications with gods and spirits - so that fits with gods and spirits being the actual source of creativity.
Also, altered states of consciousness entail a turning-away of attention from the social world - which is necessary but not sufficient for turning attention towards gods and spirits.
And creativity entails that communications be understood; so the creative person requires some knowledge, skill, expertise in the area concerning which he receives communications.
(There would be no point in sending a Medieval peasant to a scientific conference to hear a presentation by Einstein; the peasant could not understand it. Likewise the creative person receiving a communication from spirits or gods must be able to understand it - hence the results of creativity are only useful when associated with sufficient intelligence, knowledge, skill etc.)
But creative genius is very unevenly-distributed - with some tempero-spatial concentrations (such as Ancient Greece, or 16th century England, or 18th century Scotland) and other areas and eras when there has been nothing of the sort discernible.
The first reason is that creative genius requires other factors - such as intelligence. But some areas and eras with high intelligence have been uncreative.
So, why would some individuals of some religions or nationalities or races or times in history be more sensitive to communications from gods or spirits?
First there is the gift of creativity (latent creativity); then there is the deployment of that gift - Clearly, uncontroversially, in some times places and persons expression of latent creativity may be encouraged or rewarded - or else discouraged and punished.
But what of the gift itself, the latent creativity?
Since the creative communication is from gods and spirits to a Man, then the gift itself may of of the same origin.
This would imply that creativity is a destiny; and a destiny which may be accepted, perverted, or rejected; by human free will, human choice).
Or perhaps a better word is 'calling': to be creative is to have a calling.
So, latent creativity is a gift and a calling; but whether it is accepted is an individual choice; and whether latent creativity is expressed is (at least partly) a societal choice.
How common is the gift of latent creativity? I would say, not very common - although because it is latent, the frequency is hard to be sure about.
And the gift may be abused, the calling perverted - and many creative people choose to use their gift of creativity for evil purposes.
Indeed it is possible that most people with a creative gift and the calling to be creative do indeed misuse the gift and pervert the calling, due to the sin of pride: evil geniuses are very common among geniuses.
But, at the bottom line, I would have to regard creativity as a divine gift; and its disposition therefore presumably a consequence of some divine plan.
Again I emphasize, Man's choice, influenced by societal choices, can and does often subvert and sabotage divine plans.
Nonetheless. I would infer that the times and places and persons of exceptional creativity were no accident; but that God had some particular (perhaps general) hope, strategy, intention for those times, places and persons - some latent destiny for these; whether or not this destiny was accepted, and whether or not it was allowed to be expressed.