Another factor to consider is the mental capacity of the people who generated these myths. We have to remember that these stories emanated thousands of years ago, even before writing was invented and when language itself did not have a comprehensive vocabulary. But man has always been plagued by questions, our innate desire to know, to solve problems and to make our choices is the outcome of these questions. This is what makes us human, the dominant species. Some of the first questions asked by humans are still being grappled with thousands of years later - Who are we? Where did we come from? What happens after death? Some of us find our answers through our respective religions, while others are trying to find their answers in science.
Now lets get back to our ancestors who did not live in a world like ours where we have mastered almost every aspect of this planet, theirs was a different world. A world where they were fighting to survive, where the first time someone lighted a fire it must have seemed like they had harnessed cold fusion. Is it a wonder then that many ancient religions like Hinduism and Zoroastrianism worship fire? When humans discovered fire, they discovered cooking, and this gave us the ability to eat a variety of food otherwise indigestible by us, this variety in our diet enabled the human brain to evolve and grow into our present state. So if a myth states that fire destroys as well as creates and is therefore a force to worship, it is pointing to a significant historic event.
In a world frought with danger mankind instinctively looked for a "Higher Force" to protect it. And they found plenty of things around them which were much more powerful than any human, things like the forces of nature, animals etc. These then became our earliest objects of worship, as we evolved and looked up at the night sky we came to the conclusion that this "Higher Force" must be looking down at us, seeing everything, hearing everything. But we still could not comprehend the concept of Omnipresence of a single God, so we started deifying each attribute of this "Higher Force". In most ancient mythologies including Hinduism, Greek, Sumerian etc. there are a pantheon of 'gods' but there is always on supreme god who rules over all of them.
The mythologies of the different religions is our earliest anthroplogical as well as historic account. What is needed is to study the similarities of these ancient stories from various parts of the world and highlight the common threads, because they hold the keys to our past.