Earlier quoted context omitted.
I ascribe the creation of God(s) to sub-rational behavior - paredolia, superstition, emotion born of fear and ignorance. The pinnacle of intellect was realizing the universe operated by rules that could be understood rather than the capricious will of supernatural forces.
If we've already reached the pinnacle I guess we've no more to achieve bar amassing a bunch more salient observations regarding how the universe ticks. The it's job done! Almost Boring.
But all of modern science, including relativity (which is also mentioned somewhere) depends upon the initial insight that the natural world doesn't require supernatural explanation.