The FAA safety system was run by middle rank officers with no prospect of further promotion and this gave them the independence which must be an essential component of any safety regulation.
Er, no. The FAA had a culture which allowed those running the safety system (including Boards of Inquiry etc) to operate with an independent mind and without any fear that the "higher ups" would place pressure on them to alter their view or follow a different track. The FAA really did operate a "Just Culture".