No, and no one really does. But, as a head coach, his actions (or non-actions) have impact and rippling effects. You can't ignore it, these guys are not paid millions of dollars to yell "Line change!"
And, if you watch the video, the analysis is obvious. But so were some of the choices. The things that held Lafreniere back were:
Ice time, both ES and PP
Skating
Work ethic (shift to shift, not talking about summer stuff)
Being told to play a game that wasn't his game, affected other players
And then let's add in the overall lack of continuity with the lineup that affected everyone
Now I don't blame Gallant at all for 1-3. But 4-5 rest directly on his shoulders.