Since it's certain that debris deflectors would have stopped the piece of tyre that punctured Concorde's fuel tanks in the fateful Air France 4590 disaster and caused an explosion, why are they not installed on most modern aircraft? They could prevent a similar incident in the event of a tyre explosion or other, even harder metallic debris that can be tossed/deflected onto the fuel tanks by the tyres spinning or the wheels.
Wouldn't this modification have saved the Concorde? Cost of maintenance aside, should it not be a requirement on all aircraft? Do they leave it off for aesthetic reasons?