I'm not sure that approach to regulation would entail a minor increase in costs. Thorough design review and testing of a complex system is far from cheap and would require a lot of in house expertise and facilities. It would massively increase the scope of agencies like the FDA and FAA.
Why shouldn’t regulatory agencies have expertise in the industries they are intended to regulate? Government by corporation or consultant is not democratic. Without internal knowledge, government will always play the fool because it won’t know any better.
