Yes so essentially as you describe it - spirituality/religion was necessary in order to control the instinctually driven human beings enough such that some semblance of co-operation could eventuate. This allowed human kind to reach the current stage where freedom from both the instinctual passions as well as any belief in spirituality/religion can be considered.
What I am considering is whether spirituality/religion (and the worldview that it spawned) was ever necessary in the first place or whether it was actually a detour, or as Richard wrote “a retardation”.
Those humans 3000-5000 years ago were capable of considered thought like we are now. Of course there was a challenge to be faced, which is as you wrote the fact that they were instinctually driven (just like we are now). But the question is - did spirituality/religion actually assist in facing this challenge? Or did it merely perpetuate it?
Those holy men proceeded into the unknown but stopped short of the unknowable, instead of actual peace on earth they chose eternity for the ‘self’. Now here we are 3000-5000 years and much bloodshed later with the same challenge still to be faced.
There is no reason why those holy men could not have gone all the way, instead they became enlightened and brought insanity back with them. This insanity is the song that ‘humanity’ has been dancing to since, with sanity being merely a luke-warm version of the insanity of enlightenment.