I don't think he did either, but I also felt that the Legion and NCR didn't. They both just wanted to expand, at least House had saved New Vegas from complete destruction and had been keeping order. Sure, the courier could have took over, but what about after they died? Anarky.
At least you were kind and killed him, instead of letting him sit out of his machine XD
To be fair to the NCR, the president doesn't care, and likely most of the senate, but there are atleast some Citizens, Soldiers, and Officials who care about the people in the Mojave. One of the Ideals of the NCR is to help people, and there's still got to be a lot of people who share Tandi's beliefs. The NCR might want more territory, but they also want to help.
That being said, I realize that a lot of the people of the NCR want nothing to do with the Mojave, and almost rightfully so. After the NCR annexes the Mojave, they really need to stop expanding, and focus on their own Infrastructure, starting with taking care of the impending famine, and by buckling down their security and protection of their towns and cities. After that, a reconciliation with the Followers will do them some good. The NCR, while having some pretty advanced technology (likely from Vault City joining the NCR), are too widespread to make any damn use of it, and the Followers could help with their advancement in Medicine while the OSI focuses on getting more factories operational, and hopefully some military advancements such as building robots, or Power Armor to aid in the defense of settlements, and help in the patrols. Hell, just them being able to find a way to replace the more perishable aspects of cars would be a great boon to the Economy alone.
i should probably stop here, since I'm starting to diverge from my original point, but yeah. Some people in the NCR do care for the Mojave, but the leaders don't, Which is more than one can say for the other factions.