If my math isn't off, the USAF has 18 squadrons of A-10s, 5 of which they want to retire. Still leaves a dozen A-10 squadrons.
Oh, yea, forgot: they feel the A-10 is so valuable, that they reduced the number of squadrons, so that there would be far more available "fresh airframes" to greatly extend the operational life of the aircraft in service. They don't need 500 of them to stop a giant tank invasion...but they do want to add 20-40 years of service to this plane. So they wrap up a few in storage, for when the current ones are truly worn out. But give them a few days and they could put them all in the air again.
BTW: they also are rebuilding parts of the wingboxes to be stronger and last longer than the original design...I think a member of SimHQ was showing us a bit about that (Dice?)