John Carmack on a shoestring budget nearly got this working at Armadillo. If he had more money and time he would've had it working a half decade before SpaceX.
"Nearly" and "if he had more money and time" is "no".
And given how much faster SpaceX has been than anyone else, I can only believe this "could've, would've" in form of the slightly longer hypothetical "if only Carmack hired all the rocket scientists (and raised all the money to give them freedom to go fast) before Musk got there".
I love Carmack, but having an idea for something is infinitely easier than actually successfully executing on it, especially as incredibly successfully as SpaceX.
Rocketry involves building a lot of prototypes and blowing up a lot of things when mistakes happen.
Carmack did execute, they had a working rocket, and with time they could've solved the software issues, but they didn't have the funding to blow up dozens of prototypes.
Carmack drove that project, he wrote code, he built rocket engines himself, he ran missions.
Elon, notably, doesn't do any of that. He just had more money, or was willing to commit more money, to seeing it through. For Carmack it was more of a fun diversion (the X Prize) than a business he wanted to build.
In general I think what is so often missed on HN, which is so ironic given this is in big part a board for founders or those who aspire to be (I thought), is the challenge and effort and success of building companies and teams that execute on larger than life projects. It is incredibly hard to recruit the best talent in the world, and assemble them and make it work. The leader must be incredibly competent and believable to do that.
You left out a tier, and that's the embittered one with an axe to grind. It's the "nothing ever happens" crowd, and they want to destroy anyone who stands as a counterexample.