What I think is that the story is , of course, symbolic. The garden of Eden was a place that was like heaven, where there is no duality and no good or bad.. just bliss..
When they left the garden for eating the apple, it is symbolic of coming to a place of duality and right and wrong, Earth! The apple eating was symbolic of this change into duality where there was suddenly something that was right or wrong.
It was inevitable that the apple was eaten as it is unavoidable to live outside of duality when we are in this body and consciousness. This is a dualistic universe!