I think I see what you're saying, and it narrows the inquiry down to the point where you basically have to agree with your position.
Because for religion not to have existed, human nature would have to be fundamentally, and wildly, different than it is. Because we know that we have evolutionary traits that predispose us toward belief. It was, at one point, evolutionarily advantageous. So to say modern society could exist without religion is to say human nature had to have been wildly different since our inception as a species.
So sure, on that technicality, I'll agree. But in terms of whether it's still necessary, or is better/worse because of religion, my earlier posts cover my position in full.