Does the law of parsimony historically show that natural phenomena can explain the existence of theism?

..or does prehistory, dating back to the first known animistic cultures, show that humans have generally tended to at least hold beliefs in the spiritual? If anthropologists have credible evidence that humans were religious 300-50 thousand years ago, wouldn't that imply that being religious/spiritual was more of a natural state of existence while some of the more modern and doctrinal approaches to religion are modern symptoms of social decay and decadence?