It's pretty much a given that most metal bands don't usually have or need a full time keyboard player.
Groups like Blue Oyster Cult and Metallica really don't rely much on keyboard voices as a rule.
If memory serves me correctly, I don't believe that Frank Zappa used a lot of keys either.
Back in the 60's and 70's a lot of groups were basically a guitar or two, a bass and drums and that's all.
Then again, these were groups that never really appealed to me in the first place so while a few of them may have been multi instrumentalists or picked up keyboards later on, at the time, their act was basically rhythm, bass and lead on strings.
Don't forget that keyboards were crazy expensive back in those days while guitars were dirt cheap. Sure nowadays any garage band can afford a decent Korg or Roland or Yamaha but back in those days a used DX7 or Hammond cost as much as a decent used car.
Gary
