I used to think that Polly, but almost every coach in every sport says that in-game tactical changes are wildly overvalued by fans and the media, and probably account for only a very small part of a coach's job.
That is correct, Morgan, the coach is busy with whiteboards, witches hats, which players to throw under the bus this week and counting their moolah, so in successful teams, the in-game tactical stuff is left up to the leadership group on the ground.
Which is why most coaches say it is overrated.