The problem is real though. It stands to reason that the people that know how planes can be built safely are the one building planes; otherwise you could get in a situation where "those who know, build planes; those who don't, tell them how to do it".

There is a similar problem with financial regulation; my understanding is that the knowledge transfer between industry and regulation there is solved by the equally problematic "revolving doors", where people alternate between regulating and advising companies (and thus as regulators they don't want to make too many enemies).