i'd agree 100%. With all the named spellcasters who invented seemingly half the known spells in the multiverse, events like the Invoked Devastation and the Rain of Colorless Fire plus all the magical items (vorpal swords, intelligent items, frostbrands, flametongues, hammers of thunderbolts, staves of the magi and power, etc. etc.) plus all the artifacts and relics, plus the laser guns floating around; and the underground is apparently so suffused with magical power it automatically makes mundane drow equipment magical - how could you possibly think that greyhawk was low magic?? now, do you trip over 25th+ level spellcasters like the forgotten realms? no; but the FR is ridiculously over-the-top high fantasy that greyhawk wasn't trying to emulate.
TSR published at least one trying-to-be-low-magic-but-ended-up-just-being-annoying setting, Lankhmar. Compared with that place, Greyhawk is awash in magic.