Not sure if this has been said already so I apologise in advance if it has.
Please read before saying it's completely impossible.
Basically, I believe there is a chance that Naruto will eventually surpass even the SO6P. Firstly, this is based on the possibility that Naruto will become the Juubi Jinchūriki as there is no way he could ever beat the Sage, even with his current BM. We know that the Sage was the previous Jinchūriki but he did not collaborate with the Juubi like Naruto is with Kurama at the moment. It seems to me that he kept the Juubi at bay, restrained it when it was inside him and tapped into its chakra pool when he needed it, much like Naruto's KM.
Later we find out that the amount of chakra Naruto can access in this mode is "minimal", unlike BM of course.
There's a couple of pages below that suggest Naruto is the Sage's successor in terms of bringing peace to the world or maybe just the one that will rid the Bijuu of the hatred that has built up inside them throughout generations.
It has been shown that Naruto's chakra when in his new BM is immense in comparison to even his KM so I imagine the power available to Naruto if he becomes a perfect Jinchūriki for the Juubi will be many times the amount the Sage could access. I think this massive power boost may be enough for him to surpass the Sage, even when he had the Juubi.
First time posting a proper thread so sorry for any mistakes.
Let me know what you think and discuss
EDIT: I am in no way saying that Naruto's techniques can even compare to what was available to the Sage due to the Rinnegan and being almost God-like just because of his genetics. I just think that Naruto will eventually surpass him in terms of raw power; not on a one-on-one match.