.....
If Space X is able to send humans to Mars sooner than NASA, even if with NASA cooperation (if NASA figures out that Musk is really going to make it, they will jump on board), Musk will have his deserved place in History, side by side with Von Braun and Korolev (forget about Gagarin or Armstrong, beside courage, they had little merit).
Korolev, yeah.
Musk cannot change basic economics.
The way I'd do Mars (seriously) is lots of robotic explorers.