Board Thread:Theories and Speculation/@comment-26894845-20151212061943/@comment-3965545-20151213023732

It takes recreating Six Paths Chakra or Hagoromo's chakra. Therefor Obito who is a direct descendant of Madara as the manga said, should have been able to awaken the Rinnegan... my theory as to why he didn't is because he did NOT have both of his original eyes as Madara told him he needed. When he finally had them at the end before he died against Kaguya he was dying and low on chakra when Naruto revived him. I honestly and fully believe if Obito was at full health/chakra and was not dying he would have awakened dual Rinnegan. Plotwise there was no reason or time for it so it never happened. Sasuke only got a specialised Rinnegan for plot sake and main character sake.