Concorde didn't need to cease flying when it did.
Even with the one and only crash (a crash not as a result of a defect with the plane) of this marvellous bird's history and the fact Airbus ceased maintenance support Richard Branson wanted to take them on. BUT even though the British concordes where owned by the government and British Airways received big bucks to fly them, British Airways didn't want them to fly anymore.
The sad fact is that all tooling and plans used in the manufacture of the plane are no more so the costs to make one or keep an aged one in the skies would be prohibitive.
The running costs and noise of the engines used in concorde compared to modern passenger planes would also propably make it a non stater as well.