NASA’s budget isn’t the only reason SpaceX has been able to innovate faster. NASA is incredibly risk averse, as their failures reflect onto the US government and by extension their budget. Even when safety isn’t important such as with unmanned rockets, NASA doesn’t want news headlines blasting them for their rocket’s tendencies to blow up. SpaceX, by being a private company, is free to take risks and have rockets explode (if they’re unmanned that is) without much repercussions as they’re a private company, not the US government. They’ve had 7 unmanned rockets explode and several more reusable lander’s fail in their course to develop cheaper, reusable rockets, which had NASA done themselves would have been a national embarrassment, but because it was a private company they were free to take those risks to learn from their mistakes