As there is no 'national security' issue (that cloud which the USA so often hides in) then why could not an application under 'freedom of information' challenge this 2073 blockage? Surely, under the philosophy of 'everyone can learn from others mistakes' the true causes should be fully investigated and published. There have been some crashes, e.g. Concorde, whereby there are still people dissatisfied and in disagreement with the official report, but to my knowledge there was nothing locked away for this & the next few generations.
By doing so it adds credence to 'cover-up' claims.