Greco,
You are confusing intelligence with knowledge. Those past 'intelligent' people were using the best 'theories' that were available at the time and without modern science everything appeared to have magical qualities.
As more information and real knowledge becomes available, i.e. through the discipline of science, we see that the more intelligent among us can see the difference, quality and truth of the new information. Unfortunately the less intelligent appear unable to tell the difference and instead prefer ancient outdated superstitions and religion.
Consequently it is no surprise that the more highly educated and especially those who work in science are the least religious.
Provide Newton with all the tools and knowledge of modern science and then lets see what he would conclude. Until then your comparison is invalid.
Although I think your last statement is in agreement with my perspective.
Kat