Greece and Rome had very advanced moral frameworks long before Christianity came along. The educated classes didn't by and large believe their culture's polytheistic deities to be real, and morality was separate from religion considering that said deities were portrayed as behaving abominably anyways.

Over in the East, Confucianism was the prevailing moral framework, and it was secular. The Taoists combined religion with morality, as did the Buddhists, but neither managed to achieve the same level of hegemony in any large Eastern country like Christianity did for Western countries.

Dharmic religions resemble Abrahamic religions in terms of meticulously tying together a specific metaphysics, cosmology, epistemology, ethics, and even politics together into an all-encompassing system of thought. Plus you have monotheistic traditions like Zoroastrianism to contend with, not to mention Gnosticism.

Once a religion of the magnitude of Christianity starts falling, it might not be possible to stop it. Dawkins may be a materialist fool, but maybe we're at a historical moment akin to the fall of European "pagan" religions.

Maybe Mormonism or Gnosticism or Buddhism or Zoroastrianism or something we've never heard of will become the next big thing for Western societies in the coming millennia. People are becoming more curious about esotericism and the occult as well, though I strongly advise caution for anyone thinking of going down that path.