Why am I not surprised?

Yesterday, I heard that a contributing factor in the Columbia disaster was old heat-shielding tiles.  The tiles were made all in one batch, and kept in a warehouse as they were needed.  Since the shuttles were over 30 years old, the tiles were also over 30 years old, and subject to a greater risk of failure.

Not that it was the cause of the disaster, but what if the tiles were newer and stronger?  Then the shuttle may have survived.  Maybe.  There's no proof of that, or if there is, it may be covered up.  Come to think of it, I wouldn't be surprised if that were the case.