Neither is true IMO but musk just picked the right development model.

Big space never did this because the current megaproject cost plus is just what they want, a blank check.

Witn SpaceX Musk was mainly wasting his own money especially in the beginning. So it made sense. It just makes sense, it's not even a 'shortcut'.

Ps yes he did get some grants but not beefy unlimited ones.

Another thing SpaceX has going for it is when their tests fail everyone just points and laughs at Musk. When a NASA launch fails the taxpayers don't want to pay for it any longer.