Simple: experimentation. Part of what I love about the Bible, is that it is filled with people who put their religion to the test, and part of what I love about my God, is His willingness to be tested.
Well, when you get right down to it most religions teach the same stuff: Don't do stuff to other people you wouldn't want done to yourself, don't sleep around, don't cheat, don't lie, don't kill, don't steal. Et cetera.
That's just your basic moralities. If people want to build on them and make them gods they might as well. It's the way of humanity, I suppose. We can't explain something, so we make something up which seems to make sense to us. Thousands of years later we've found out more about the world and we can explain those things, but some of the beliefs stick around in traditions and religions. Not everything is based around texts.
I'm not sure if I'm opposing you or backing you up. Well, I'm just stating my opinions, people don't have to listen.
But how could the word, record of the word, and such exist if the concept of written word or oral tradition didn't exist? What of the time before man? How did they that this written word existed before the first particle?