Even Martin Luther didn't believe in Biblical inerrancy, he did not equate the inspired word of God with perfect wording. It's the flat headed Fundamentalists, who are also Zionists, who are literalists and dictators of interpretation.
I don't think it would have been possible to convert Europeans to Christianity if it denied that their ancestors were worshipping God. Actually, it's clear that Arianism, the first Christianity adopted by Germans, acknowledged the existence of their old gods. They just accepted the divine life of Jesus as the son of God and his resurrection.