1. US government contracting preferentially selecting over the last 75 years for people who are used to working slow and dotting every i / crossing every t -- i.e. business as usual
2. Regulations during business as usual slowing down the maximum throughput of processes
That isn't to say that other people don't still exist in the US, just that they're not currently at government contractors, because the government hasn't prioritized their core competencies (speed).
It's entirely possible that, similar as was done to military command staff at the outbreak of WWII, the US rewrites its regs, fires people who are incompetent at working at a faster pace, and recognizes and elevates talent.
Unfortunately the current executive branch, while tearing down regulations, then has more interest in profiteering and nepotism than truly pushing exceptional engineers.