Some people wouldn't believe their account even with 500 witnesses, four documented accounts, and a 2-billion person following.
Make that five. Paul's account of his conversion with the risen Christ.
But your analysis is correct. In fact, did not Christ Himself say in Luke 16:31 - "But he said to him, 'If they do not listen to Moses and the Prophets, they will not be persuaded even if someone rises from the dead.'"