The offense carried the Sox in the '21 postseason and shouldn't be blamed for whatever Houston did to totally shut them down at the end. But it's no surprise the team that did win it all had solid starting and the best bullpen.
In two playoff series, the Boston relievers were not good enough to get us to the World Series. Robles (twice), Braiser, Barnes, Houck, Sawamura, Darwinzon, Ottavino, Taylor and even Whitlock all took turns coughing up leads or giving up runs. Yes, they were overworked because the starters were just adequate, except Sale, who wasn't even.
Bloom chose to address the depth in the rotation and bullpen by adding Wacha, Hill, Strahm and Diekman. Those were the upgrades to take this contender to the next level.