Re: "If at first you don't succeed... you're probably NASA"
I just don't get your point.
When you start building rockets, things will go boom during development. You can either spend vast sums trying to prevent this (and likely failing anyway) or do iterative designs with cheap prototype that you expect to not have a long life. Whether it fails or not, you incorporate the things learned into the next one so even if it doesn't fail it is likely to be scrapped and not fly again. You effectively don't care if it goes bang, you have got the data either way. This allows very cheap, very fast progress.
NASA had their fair share of failures when they started out too, when they were doing iterative design. A few minutes searching YouTube will find you many spectacular NASA launch failures. Very few SpaceX rockets have failed during launch phase, even their test articles as this was all based on stuff that had been done before. Their failures were pushing the envelope to do something nobody has tried before. Propulsive landing of an orbital rated rocket. Most of these "failures" were tests using rockets that had already completed the mission they were built for, so didn't cost anything.
I doubt if all of the money spent on all of SpaceX "sacrifices" match just one of NASAs kabooms, not to mention the fact that several NASA failures also killed astronauts (Apollo 1, Challenger, Columbia).
NASA can't afford to do this sort of program with SLS as the engines are in a limited supply and they, along with everything else to do with the system are astonishingly, eye-wateringly expensive.