Does any muslim ever wonder if Mohammad just came up with the Koran and just spiced up some stories?

Mohammad sounds a lot like Joseph Smith, founder of the Mormons. It just seems like Mohammad found a way to rise to power by adding a little spice to some other stories circulating and then said an angel gave him these "truths" Do Muslims accept it blindly from Mohammad and does penalty of death deter people from being outspoken in the mulim world? peace