I worked for over a decade on one such technology. It finally did go commercial on a scale less than what was envisioned. A major problem we had was have priorities shifted by upper management way too often. It had some massive problems, most of which were somewhat solved, but what happened really was the criteria for success were just reduced to a point it could be made at some scale. I am pretty sure the stuff they made wasn't very close to the actual performance specs for the material.
They would not let me check. Ha.
