Not being their reincarnations (duh) but more in a literal sense, they are exactly in the same spot Indra & Ashura was in terms of building a clan/linage. Madara/Hashi were different, their bloodlines didn't stop at them at the time. There are only 2 Uzumakis and 1 Uchiha left. People only seem to concentrate on Sasuke, and him rebuilding the Uchiha clan, but seem to forget about Naruto building a clan of his own, obviously Uzumaki. Both clans are extinct, so it would only make sense for Naruto & Sasuke to be successors of a new generation of clans, just like Ashura and Indra were. And for the bloodline to stay inherently intact (yes, I know Naruto isn't full Uzumaki, but he carries more traits of them than he does his fathers), it would also make sense for Sasuke to companion Karin, and Naruto to companion Hinata (sorry Sakura fans).