Chucks-
Concorde was a wonderful technical accomplishment but it was damaged by economics to the point where it just didn't pay to continue flying it, I think. It was not grounded due to safety, having been successfully modified post-crash. I think we could put it in that corner of aviation with the Graf Zeppelin, the Spruce Goose and the Saunders-Roe Princess, technical successes but economic failures.
I was in the BA Engineering Directors office at the time the fleet was being stood down. I said to him it was a shame we were going to stop flying them. He said to me "They are just too dangerous" Or words to that effect. That may well have been a personal view of his and I'm sure the decision wouldn't have been his alone. Economics must have had a hand, after all economics and safety can't be separated in most fields.