Gai stops Obito, killing him, the rest of the alliance manages to stop Madara together, Sasuke arrives and sees the fight has ended, tries to do the same as he did after the war ended, kill all five kage and the Bijuu. He's killed when the Hokage fight back their control from Oro like Hashirama was shown to have been able to do very easily. Years pass and the Last happens, Sasuke isn't there to protect the leaf from a big ass meteor, so everybody dies. It is arguable wether Naruto gets his Ashura chakra or not and manages to stop Toneri, but regardless, if he does, this leaves Hinata, Naruto, Shikamaru, Sakura and Sai (Or Neji if he's the one to have replaced Sai, being still alive and all) as the last living remnants of the Leaf. Everyone else died because of that meteor.
Don't know what happens then, but that sounds like a sh*tty ending for everyone involved. Naruto probably becomes a hermit or something after his home was wrecked alongside almost all of his friends and the title of Hokage made worthless, destroying everything he ever fought for alongside his dreams. Neji ends up with Hinata, Shikamaru with Temari, Sakura dies alone