When? He sure as hell let him audible from 2007 through 2019 when he got hurt. It's a cheap argument. I don't know why the hell he didn't let him after that, if he truly didn't. It was a stupid decision on his part, no argument there.He would not let Ben audible.
Tomlin's issues and limitations create same with the team, and these issues have been the same since 2015ish.
That being said, I think this audible thing is overrated. My buddies and I used to joke about it when we'd watch Steeler games. You'd get all excited, you'd see Ben pointing an shiit, announcers saying "he's audibiling!", blue 52 and all that, the play would go off and it wouldn't be much. It started to become funny. I can't remember any, but can you recall one big play Ben had that sticks out that you were sure he was audibiling? I really can't. Audibiling and improvising are two different things.