All that lack of evidence proves is that if Jesus did exist his life and death were certainly not accompanied by all the miracles listed (e.g., the darkness after his death would be just the thing for someone to report widely). It is a bit like a field of wheat. If someone reports that an elephant walked across it last night, one would easily see the signs (lots of broken stalks, footprints, etc) and lack of such signs would cause one to doubt the report. If someone reports a mouse walked across it last night, that would be a bit trickier to find the signs.