Board Thread:Naruto Discussions/@comment-34436445-20180703141210/@comment-36015788-20180703151201

Well basicly, I think it mostly from the fact Kishimoto wanted Sasuke to keep his sharingan, since its iconic to him and allowing him to use his MS abilities togther with the Rinnegan. Though I am pretty sure his 6T Rinnegan should be equal if not more powerful than the normal 2 eye rinnegan considering he awaken it from receiving half of Hagoromo chakra.