Because Naruto isn't an Uzumaki. If you remember the chapter where Kabuto talks about Karin, he talks about their distinct Chakra - leading to a larger lifespan - and their special red hair. Karin's distinct chakra was again pointed out by Tobirama. Hence, whatever Kabuto learned, Orochimaru knew as well. This much is certain in regards to revering the Death God Technique in the Uzumaki scroll he had hidden away.
Naruto is a hybrid at best, pretty obvious from the fact how he immediately died when Kurama was pulled out, where as his mother, Kushina not only restrained the nine tails for quite a long time, but managed to set up a barrier as well. In fact, she would have lived even longer had Kurama not stabbed its claw through her says a lot about her stamina and endurance. Naruto cannot even match half of it.
With Sasuke, Orochimaru would get the eyes and then the Rinnegan. He also needed a stronger body to master the Dragon Sage Mode, which is why he experimented on Sasuke's body in regards to senjutsu to see how he handles it. He was successful. So, in short, Sasuke was this ideal host for his pursuit of immortality - Rinnegan grants to you.
I am unsure what he would have gained out of a hybrid Uzumaki at best.
