Well, I’d argue they quit when they decided a guy who literally can’t throw the ball past the LOS should continue to play QB.
Outside of the fact that the defense knows exactly what they’ll do every play, there wasn’t enough time to “establish the run” in the second half.
The Niners coaching staff quit on the team. No, an emergency QB wouldn’t have saved the day. But having a guy with a functioning arm HAS to be the better option.