I don't like to be flippant, but with 20/20 hindsight—I believe one of the members mentioned that—we know a lot more now than we did then. Often in aircraft accidents—and there have been many throughout history—what we learned from that accident was not known by the designer nor by the regulator. It became common knowledge after the fact.
This is a situation where we learn and have learned about failure modes of the MCAS, how it relates to the basic architecture of the airplane.
I can assure you if we had had any of that knowledge at the time, we would have been digging a lot further, but with the aviation industry, as with the automobile industry and any other product that's produced, when things go wrong and things break, those are opportunities where we learn things we previously did not know.
It's not a question of negligence unless somebody is deliberately hiding information. That's a completely different subject. This is simply a question of what we learn after these accidents.