[drivebycomment]

> This seems like a huge failure on the part of the NTSB.

This is a deep misunderstanding. NTSB is not an organization with a regulatory power - it is an "investigative" agency. It does not have any mandate or power to stop anyone from doing anything. It can investigate and issue recommendations and reports to other agencies that have the actual power - FAA, FHA, NHTSA, etc, etc.