Luke 16 - Proof

Yesterday I heard the question raised, why did Jesus spend his 40 reincarnated days with so few people? He proved to them he was alive again, but why not prove it to the world? Wouldn't that have made things easier for the disciples after he ascended?

Apparently not: "If they do not listen to Moses and the Prophets, they will not be convinced even if someone rises from the dead."