Bullpens in the day were stocked with washed up old arms and unproven youngsters. Complete games were certainly common.

during his time, so good point.

Armless Joe Jackson, #7, always hoping for a walk.

A contemporary of Bob's. Faced each other multiple times each year. We saw 3 Gibson wins. 1-0, 1-0, & 2-1, over 3 years. Two at Wrigley, one in St. Louis. Late 60s.
Fergie had 284 wins & 267 complete games! Not more CGs than wins like Bob, but more of both.
Given how baseball is today It's almost hard to believe 2 guys pitched over 500 complete games whole in the league at the same time.
There were 35 complete games pitched in the whole major leagues this past season. 35. It would take 15 years for all of mlb to have as many complete games as these 2 guys.


https://www.baseball-reference.com/players/j/jenkife01.shtml

Nobody wanted to be on deck when the guy at bat hit a HR off Gibson.