I don’t understand though – we have fighter jets going at mach 3 and mach 4, and they use far more fuel than Concorde did, and are flown regularly. Surely the Concorde could still be used, but the number of flights could be even more limited, or it could be used for air-shows and stuff? It’s just such a waste to have such an amazing aircraft sitting in a museum all day long.
Another thing – there would always be a market for concorde for the super-rich. Make tickets slightly dearer and it would make a profit.