Is there any reason to conclude that the Paleolithic and early Neolithic documents were not similarly reinterpreted over time, but that the nuances and details of belief where such changes would be visible are not apparent in the "documents" that survive? In other word: Eliade describes a continuity in religious belief demonstrated by cave paintings and other durable records which seem to have remained in use for thousands and tens of thousands of years. Similarly, similar, but albeit fairly simple, statues are left over long spans of time. Does this guarantee a continuity of belief? It seems possible, if not likely, that the last people to use those caves invested the cave paintings with a vastly different meaning than the first people to use those caves. The idea of Zeus seems to have persisted from ancient cave sites found on Crete worshipping a bull-god who died and was reborn like a typical fertility god, through the archaic era where Zeus became identified with might, authority and rule, and into the classical and Hellenistic eras when Zeus as Jove became increasingly bound to the ideas of Platonism.
