"It has been a disappointment. I'm not going to maintain status quo and hope the outcome changes," Tomlin told reporters Wednesday. "That's the definition of insanity."
The coach also indicated there could be staffing changes this offseason.
"Change is a part of our business," Tomlin added. "I'll acknowledge the possibility of that."
Pittsburgh carried high expectations after beginning the season 11-0, but it lost five of its final six games. It's the fourth straight year without a playoff victory for the Steelers, who missed the postseason in 2018 and 2019.
Tomlin has a Super Bowl title and never had a losing season in 14 years with the organization, but the team's recent inconsistency could lead to changes.
Randy Fichtner has been with the Steelers since 2007 and has served as the offensive coordinator the last three years. He guided the league's No. 24 offense in 2020. Keith Butler has spent six years as the defensive coordinator as part of his 18 seasons in Pittsburgh and helmed the third-ranked defense last year.
There had also been stability at quarterback with Ben Roethlisberger holding the starting spot since 2004, but the team could look to replace the 38-year-old this offseason despite the one year remaining on his contract.
Even after going 12-4, the Steelers could have a much different look in 2021.