SpaceX has done a fantastic job, but that still doesn't diminish what was achieved by those that went before them many years ago, or change the fact that they stand on the shoulders of giants.
The people who helped SpaceX get where they are today are the people who designed earlier liquid rocket engines, found out which propellants were best, and came up with the principles of multiple stage rockets. NASA's achievements have been stunning, and I am in awe of many, but only a tiny proportion (<<5%) of NASA's spending and attention has been laying the groundwork for SpaceX's achievements. If NASA wanted to contribute to the future of manned spaceflight, they would be experimenting with simulated Mars and Lunar gravity at the ISS.