I wouldn't say religion has stagnated, it's more of an invisible force. For example in the quote "like Saturn, the Revolution devours its children" it refers to the Roman God Saturn, a God of a religion that had been dead a thousand years and was never followed in France. Of course much like Indo European language descends from a common source so do the Gods, so the Celts would have an equivalent. This shows that Religion never disappears and only morphs with time. Atheism as practiced by the Sam Harris types is an appeal to rationalism divorced from any semblance of community and thus doomed.