Board Thread:Theories and Speculation/@comment-28939725-20161201164545/@comment-734582-20161204141754

Kakashisologod wrote: And becuse he dosent have madaras spirit/brain. Yes, this was my actual point. Similar to how kakashi couldn't deactivate Sharingan because he didn't have an uchiha brain, Nagato can't activate Susanoo because he doesn't have an uchiha brain (and can't deactivate Rinnegan because he doesn't have Madara's brain specifically).

Merely possessing Six Paths chakra doesn't grant you that or else Naruto, Obito and Sasuke would've awoken dual Rinnegan.