Just a thought, why did not Boeing continue with the 727 design, implementing more modern engine technology/hardware/software and incorporating two pilot operations on the f/d?
I really don't know the answer to that. I do know that there was a company that was going to fully modify the 72 with the -219 engines in the number one and three positions, remove the FE station and completely redesign the cockpit to allow a two pilot operation with a modernized automated electrical system. However, they never were able to get enough finical support to finish even just one aircraft.