Voadam
Legend
That seems a bit of a silly conclusion considering that wizards were artillery from the start and fireball and lightning bolt got used regularly in D&D even with treasure destroying possibilities. AD&D mages and 3rd level fireball grew out of OD&D mages and 3rd level fireball which grew out of Chainmail, where mages were actually artillery replacements in fantasy battles.Ironically, if you believe some old school blogs, the reason fireball is 3rd level and not higher is that it did expand uncontrollably and destroy all the treasure (remember those item saving throw tables in the 1e DMG?). Cone of Cold was invented as a fireball without this disadvantage, and when the treasure-destruction was removed in the transition to CRPGs (which the computer power of the 1980s wouldn't have been able to handle on top of the other stuff they were trying to keep track of), people got used to mages spamming fireball and influenced the idea of mages as glass-cannon artillery. The whole course of RPGs was affected by a single overpowered spell.
In early very deadly editions of D&D if facing a tough monster or a horde of monsters, killing them can be priority #1 over not risking the loot they carry.
OD&D 3rd level fireball:
"Fire Ball: A missile which springs from the finger of the Magic-User. It explodes with a burst radius of 2” (slightly larger than specified in CHAINMAIL). In a confined space the Fire Ball will generally conform to the shape of the space (elongate or whatever). The damage caused by the missile will be in proportion to the level of its user. A 6th-level Magic-User throws a 6-die missile, a 7th a 7-die missile, and so on. (Note that Fire Balls from Scrolls (see Book II) and Wand are 6-die missiles and those from Staves are 8-die missiles. Duration: 1 turn. Range: 24”"
Chainmail fireballs
"Missiles: A Wizard can throw either of two types of missile (select which before play begins). A fire ball, equal in hit area to the large catapult hit area, or a lightning bolt, 3/4" wide by 6" long, with an attack value equal to a heavy field gun, are the two missile types employed."