The mistake you are making is the common gamer-equivalent of
"If only we had better politicians we would have won the war, our army had such potential!". ED has been massively succesful for far longer than the average game, the idea that 'if they had used a different engine we would have everything we have now, plus more, faster, easier and better!" is literally based on nothing but gamers mistaking imagination and fevered dreams for 'potential'.
Maybe ED is never going to conquer the entire world, regardless of engine, and it never had any such potential. Maybe its not that all the professionals are wrong, but that a subset of gamers that need to get a reality check.