General Discussion

I didn't mean to say this is "all there is to it".

Yes, coming up with (what we NOW know to be) supernatural explanations for why things are the way they are did happen when humans lacked the technical capabilities to explain the REAL reasons things are as they are.

There's a number of causes for this of course, like not having reasoned out the scientific method yet (at least, not through a lot of early human history), the inability to widely share knowledge, the inability to bring the best minds together for collaboration, and especially due to the lack of instruments like telescopes and microscopes and electron microscopes, not mention a periodic table or an understanding of atoms and molecules, and the other building blocks of the universe.

When you have NO idea how anything actually works, this means ANYTHING you think of could be 'the real reason'. The notion that Zeus was a supernatural being did not occur to Romans because they had no frame of reference, they simply did not know what was "natural". ANYTHING they imagined could be completely real, for all they knew. It's only in hindsight that we recognize that their explanations were supernatural ideas, i.e. things that are not actually possible per the known laws of the universe and matter and such.

So, yes, It is fact that human beings have an innate tendency to want to reckon WHY things happen/happened.

But why? I will posit that the primary utility is to predict, or more optimally, direct future outcomes.

And in turn, ability to predict or direct outcomes confers a survival advantage to the group, and the individual. The ancient supernatural explanations you're alluding to being religions were just people making shit up, in hopes of increasing their chances of living and reproduction. Banding together and believing the in same explanations helped them make these explanations SEEM more real/reliable. This process formed the "roots" of primitive/early religions. Eventually individuals realized that if you graft the ideas of magical protection and eternal life onto this framework, you can really draw the suckers in, and make them work for YOUR benefit, control societies, get people to go to war for you (after all, you don't REALLY die when you die for your Lord on the battlefield! HEAVEN AWAITS!).

Hence my supposition that the most basic part of religion, whether its people who worshipped the god of the trees and the rain and the sun, or Zeus or Rah, or Yahweh, or Allah? It all fundamentally arose from our survival instincts.

Religions that continue to exist now in large numbers, these are the ones that hold onto ideas of protection during life, and eternal life afterward.