Just to briefly interject- it wasn't just fireballs. It could be dragonbreath.
OR JUST FALLING. OR GETTING HIT BY AN OGRE.
The item saving throw table applied to acid, crushing blows, normal blows, disintegrate, falling, fireballs, magical fire, normal fire, frost, lightning, and electricity.
Falling was a killer of potions, especially because you had a 1 point penalty for each 5' after the initial 5' of falling. So a fall of 35' (for example) would give your items a -6 on saves, and potions would save on a 13 to begin with- meaning your potions in vials would need a 19 or higher, each, to survive the fall.