I've always loved that quote--and its entirely true. Gods have risen and fallen, new ones who conveniently coincide with leader's ideals replacing those that don't. Largely, that's what led to the rise of Christianity--the Romans changed their positions from harrassing Christians to using Christianity to strengthen nationalism and grant further control of the citizens.

It's also quite apparent when one looks elsewhere--religions that preach similar values to those already held by society grow rapidly and quickly take over. But if its the "truth", it oughtn't matter at all whether the values fit a current society or not--it's the truth, people ought adjust themselves to fit it, not the other way around. But that's what's happening, people play around, changing the "truth" to fit their existing desires.