It's important to remember Christian mythology evolved over several hundred years after the events purported to occur in the Bible. During that time, multiple messiahs were coalesced into one, and the common criminal's death was slowly morphed into an Abrahamaic blood sacrifice so as to acquire additional meaning. The fact that none of the events likely took place doesn't really matter - most of the events in the entire Old Testament didn't likely occur either. The point was to attempt to construct a narrative that sort-of hangs together if you don't look too closely. In the end, the Christian myth is just another example of one myth overlaying prior myths and adapting with greater or lesser success the symbols and meaning of its precursors. The Easter story is a rather clumsy overlay on the Spring Equinox festivals, with their emphasis on rebirth and new life, but all myths have to struggle with incorporating earlier structures. The real problem for the Christian mythology today is that it was an Axial Age attempt to reconcile various social stresses; today our modern technological world has summoned forth mechanical gods (communism, nationalism, racism, etc.) and in consequence the three mythologies that originated so long ago with the cult of El (Judaism, Christianity, Islam) have all passed their best-used-before date.