Many millenia ago, we needed explanations for the immense power of nature, natural forces and disasters. Seeing the ground shake, fire and lava pour forth from the ground (which still goes on to this day in Northern Africa where man first arose) and the power the weather has over man, not just in terms of disasters, but it's ability to make our crops grow, or not as the case may be; the hold it has over our lives. This especially so when you live closer to nature.
In our modern day lives, many of us don't have the time or inclination to lay on the floor and look up at the night sky, and even if you did, there's too much light in cities to see anything. Back then people lived out in the open and would see the whole milky way in it's glory not to mention shooting stars and comets.
So - how do you transition from those days of the gods controling everything to a modern world of scientific explanation? It would be almost impossible to achieve that in one fell swoop. Instead, we see a period of transition, like the enlightenment, elongated over a period of thousands of years where mankind shakes off legend, mythology and to some extent religion, and slowly wakens to reality (as far as we know it is real), and this is why god doesn't do anything tangible now.