The 747 can fly to more airports ... A LOT more airports than the A380. Based on that alone, the A380 will never be the Air Force's choice to fly the President in.
In addition, the 747 is a proven aircraft with many hours under it's belt. The A380 is essentially still an experimental aircraft. It will need a decade or two to work out the bugs.
Sure, Airbus can waste their money bidding, but there's no way in he11 that they'll win.
-Fatty