> lead to rampant speculation considering
   > how high profile these accidents are

High profile? NTSB routinely handles aircraft crashes with hundreds dead. This is not even moderate profile for them. They do things a certain way because it works. If you start talking publicly, witnesses get intimidated, contractors and manufacturers get tight-lipped, speculation causes changes that are actually not safety-improving. NTSB has ZERO rulemaking power, by design. They have one job only - figure out what happened and make completely non binding suggestions on what could be done to prevent such cases in the future.