I think it is an easy hindsight observation and criticism of any coach when they lose a game calling plays that they themselves had full confidence in, but don't end up working out. Do we know that the 9'ers would have won that game had Shanahan stuck to the ground game? Maybe he and his coaches saw something that they really liked and went for the jugular to put the game away? Maybe they saw a change made in the Chiefs defense that was going to make running the ball more difficult? Basically, there was some thought process that went into the plays called by Shanahan and I am sure he had very little doubt that opening up the passing game was the right thing to do at the time.
How many times did fans question McCarthy when he would get conservative and wind up losing a game? Sometimes you look like a genius and sometimes you don't. Had the 49'ers completed a few more passes and put the Chiefs away, people would be praising Shanahan for being creative and willing to take some risks to win the big game.
I think the one of the ONLY thing I pin on Shanahan is how he handled the clock at the end of the first half. To not use any of their timeouts as they were holding the Chiefs in check to give his offense more time. It seemed like he was playing to NOT give Mahomes the ball back instead of just having time on the clock for his team to score. AND they got the ball to start the 2nd half.
Granted who knows what happens, but the difference that 23-10 or even possibly 27-10 makes going into the 4th is huge. Maybe it doesn't change anything because Mahomes turned into the Mahomes we expected him to be with 7 minutes left. But his defense was in control and the offense was having success. Call your timeouts.
Other than that, they had tremendous success in play action. Jimmy G only had like 5 incompletions for a while. The play down the sideline to Kittle was perfectly drawn up, and the play to Sanders with 90 seconds left he was wide open. There was another play where Kittle was wide open in the middle of the field and Jimmy G didn't even throw it to him.