Board Thread:Theories and Speculation/@comment-34661853-20181111160651/@comment-32685487-20181116150859

You need the SOURCE. You need the DNA/Flesh of a transmigrant.. which Sasuke and Madara each had the DNA/Flesh of Hashirama implanted into their hearts to repair their hearts preventing them from dying from the grievous wound. Madara did not have Hagoromo around to gift him some chakra in order to lessen the time it takes to awaken the Rinnegan, unlike Sasuke. So if Naruto and Hashirama wanted to get the Rinnegan they would need to implant Sasuke or Madara's flesh/dna into their bodies which I supposed implanting their eyeballs could work too. That is why Naruto did not get Rinnegan.