Board Thread:Naruto Discussions/@comment-26273905-20150403160041/@comment-945885-20150405205030

Naruto awakened Six Paths Sage Mode after obtaining Hagoromo's Six Paths Yang Power and the chakra of all the Tailed Beasts. It granted Naruto enlightenment, essentially giving him insight into the nature of chakra and allowing him to wield it perfectly, as an ancient master might after dedicating their entire life to training. It seems to be a sort of instinctive understanding, as he's unable to explain how his techniques work in a practical way.

The part of the databook I wasn't able to read before due to blurriness basically states that in order to master the technique, one must have "the determination to face any challenge," "the perseverence to never surrender," and "the ability to break the samsara and shape destiny." In doing so, they will be able to comprehend the flow of life and perceive the origin of the world.

In other words, it's not a result of Naruto's bloodline or heritage, but rather his personality and philosophical worldview. And, naturally his life experience is similar to Asura's.

In the same way that Sasuke still has his Rinnegan, it seems likely to me that Naruto's chakra enlightenment remains after the manga concludes. However, without access to the chakra of all nine Tailed Beasts, he probably can't undergo the literal Six Paths Sage Mode transformation (with the telltale Six Paths seal and Truthseeker Orbs). That makes the most sense to me, at least.