If it was a totally unknown and unproven material then I would have a degree of sympathy. The first commercial Jet was British - the Comet and if it had oval windows then Britain would have dominated the airplane construction Industry for the next 50 years, because we built the best engines too.
At the time we had no idea what repeated pressurisation did to aluminium components. So the first Comet flights were a roaring success, leading to American manufacturers copying their designs. However the Americans literally tried to cut corners and have smaller windows in their planes, rather than the large and beautiful square windows in the Comet.
Then Comet started falling out of the sky in pieces, all at around similar number of flights. Air crash investigation was in it's infancy but they discovered this was aircraft metal fatigue, and it particularly liked to propagate around square corners like those in the windows of the Comet. The Americans choice to go with rounded windows bought them enough time for the science to catch up with the innovation.
Aluminium had been the space age material in the late 40's and early 50's, strong, light, durable....are we seeing parallels with Carbon Fibre yet?
So yes IF Rush had been building this thing in the late 80's or early 90's he would had that excuse because the knowledge of how carbon Fibre fails wasn't there yet. However in the intervening years we have become far more aware of how the material reacts under different circumstances. He chose to ignore them and put lives in peril as a cold-hearted risk reward game he was willing to play.