That's the past. That doesn't mean it wasn't a dumb move.
Do you know what Alex Smith did the year before Harbaugh? He did 215 ypg and 1.3 TDpg, and with Harbaugh he did 196 ypg, and 1.1 TDpg. Offense went from 313 ypg (24th) to 311 ypg (26th) under Harbaugh.
To his credit Alex Smith did cut down on interceptions under Harbaugh, and they increased their PPG by 5. I'd say that's mostly due to the fact that their D flipped the field on teams. The improvement of the D (24th to 4th) was the difference-maker for the 2011 49ers.
That still goes to Harbaugh's credit, I'm just saying he's not the offensive mastermind people believe him to be. Peyton Manning is a proven offensive mastermind.