To be fair, Tom Mueller was also head of liquid engine propulsion at TRW as noted in the wikipedia link, he wasn't exactly an amateur. I had the same initial response to the gp, but I think they got it right: "The primary issue for other companies is culture and institutional ability to foster innovation and take risk." I think SpaceX went after people who knew what they were doing, but were frustrated by the bureaucracy. I get the sense that Blue Origin hired people with experience who were pretty happy with the way traditional aerospace worked, and kept doing exactly the same thing at Blue Origin.