So again, why did they not benefit? Could it be that you need multiple issues beyond not running it to get defenses to not key?
Good question, as it concerns those particular QB. I looked into their teams' run frequency, and just found more randomness
Roethlisberger's passer rating with PA has been lower or about the same with PA, with the exception of 2017, when his passer rating was 23 points higher with play action. His team's run frequency did go up that year over the previous two seasons, but only slightly (from 39% to 40%).
Rodgers had one really bad play-action year (2015) when his rating was 25 points lower with PA. The Packers ran 41% of the time that year. In 2017 his rating was 23 points
higher with PA. That year, the Packers only ran 39% of the time. The other years, there's been no significant difference between his rating with PA and without.
Carr's rating was lower with PA from 2015-17, with the Raiders running it 39% of the time. It's been slightly higher with PA the last two years with the team running it 41% of the time.
Flacco is the only one who has been consistently worse with PA, year after year. From 2015-16, his team only ran 34% of the time, and his rating was 7 points lower with PA. The next season, the Ravens changed philosophies and ran 44% of the time, and Flacco's rating was 23 points
lower with PA.