Columbus' 4th voyage has been a total failure: he has not found the westward passage, he has no gold to show, he has lost men and ships and his efforts to build a colony have fallen through. The monarchs of Spain are not going to restore the rights and privileges which were taken away from Columbus after the first voyage. And Columbus will be shamed. Many of his sailors who have survived, can't face the journey home. They will choose to remain on Hispaniola or neighbouring Puerto Rico.