I basically agree with you. I generally don't like Stubby's conservative strategy to preserve a win by pounding the pill, mainly on the grounds of what hoosier said: you risk losing that scoring momentum.
But Stubby's never gonna change. He's old school Steelers. He WANTS his team to be able to control the game by pounding the rock. He's said it countless times over the years.
The problem is IMO the game has changed. You CAN'T control the game by pounding the rock anymore. It's now a pass-first league. Even the rules favor the passing game. Few games are truly out of reach no matter how far behind you are. And Stubby kinda understands this too because when he needs points he reverts back to passing like there's no tomorrow.
So he's caught in a kind of contradiction: his instinct to control the game by rushing vs the reality that you score points (and convert third and long) by passing. IMO that's why, in so many of these games (and end of game, crunch time scenarios), Stubby's approach seems schizophrenic.