There are a lot of challenges in creating a moon base or Mars base beyond getting stuff into orbit, which is quite routine in the commercial sector.<p>NASA should have no shortage of interesting challenges even if they outsource launch services to get more bang for the buck. 
NASA does some great things with planetary probes, etc., but their manned launch systems have always consumed prodigious amounts of money.<p>By contrast, the money SpaceX has spent to almost complete the development of their new NASA-funded launch system is approximately 1/20 of the projected <i>cost</i> <i>overrun</i> of the internal manned launch system NASA has been working on (the Aries I).