Prior to the establishment of NTSB in the Air Commerce Act of 1926, aviation accidents were common [1]. Congress determined that it was necessary to establish an investigation and regulation framework immediately at the beginning of the era of commercial aviation and this has been enormously successful. Many times Congress does not act fast enough to prevent harms (meat packing, banking, pharmaceuticals), but when they do get around to doing their job safety improves. Individual companies must be compelled to act subordinate to federal or state regulatory frameworks, and to not act as vigilantes.

[1] https://en.wikipedia.org/wiki/List_of_accidents_and_incident...

Oh, so post hoc ergo propter hoc?

I'm not saying the NTSB isn't important. But it's far from the only reason that we have fewer crashes. Government regulation can be helpful in improving standards, but they set a minimum bar. Aviation's high levels of current safety are a collaboration between many, many people. Starting with individual pilots, engineers, and maintenance techs, going up through collaborative relationships, through companies and civil society organizations, and up through national and international regulatory agencies. All of these people are taking responsibility for safety.

From your comments in this thread, I think that you believe that safety is a collective effort and that there is no single individual or entity directly responsible for enforcing a culture of accountability, is that right?

If so, how do you explain the catastrophic failures in construction, food safety, and banking prior to the top-down government oversight of those industries?

That is not in fact how I'd sum up my thoughts. "Enforcing a culture of accountability" is valuable, but neither necessary nor sufficient for safety depending on context. Food safety's an obvious example there. People still get sick from food. And plenty of restaurants and manufacturers would never cause illness if government oversight were to vanish.