I think you get this a lot with football, with fans across all clubs, where a Manager will either pick a player or make decisions that seem to utterly incomprehensible to the fans watching that they think the only possibility is that the Manager must be doing something so stupidly wrong, and there is no other explanation. It is one of my biggest annoyances with discussing football in general that a group of people can feel so sure about something despite having no where near the level of complete information compared to the man that they are criticizing.
Of course Managers make mistakes, just like every single human in every single walk of life. Because this is a competitive game based on a lot of random factors at an elite level, and it is impossible for any person to predict the future and get everything right. All they can do, is make decisions that they think will work to their benefit the majority of the time. Sometimes that won't work, but this post is not to say Managers don't make mistakes, but is to say that if a group of people working off of incomplete information are so, so sure of something that is supposedly so, so wrong, maybe there is something else at play? And maybe it is not about mistakes vs perfect decision making, but maybe it is about understanding the process of making those decisions and appreciating not just the short term aspect that you see in front of you, but all of the long term considerations as well.
For instance, with this subs narrative that is now creeping up. Apparently Poch is bad at subs. Apparently he either waits too long or continually makes the wrong decisions, and apparently those subs always fail to change the game. But forgetting for a second that more often than not, we are winning and therefore don't need to be chasing the game with subs. And forgetting for a second that players have acknowledged that Poch regularly makes significant, but subtle changes to shape multiple times in a game which the players acknowledge have a great effect on the overall result, consider the following: Poch is one of the most sports science conscious managers there is. He knows his tactics, he has a preferred style of play, and he is good on the man management side of things as far as everyone that has worked under him seems to say. But the key thing that probably allows us to compete with far wealthier clubs and frankly operate at a level that even 5 years ago we probably couldn't dream of doing, is because of the knowledge and faith he places in sports science and conditioning. It is a base which informs the strategy, the style of play, how you manage each individual player etc and is so important as a competitive advantage that it is what he bases a lot of his decision making on. He first built a squad, trusted in youth and established a culture at the club where he could run these players into the ground, break them, and show them that they would be better for it, so now that is established and allows them to get to a physically higher level than they've ever reached.
So when we look at his subs, or his team selection more broadly, let's ask ourselves why he is so much more prescriptive about subs, and how many minutes he tries to get in to each player (he regularly talks about getting minutes into players, playing themselves into form but there is a conditioning aspect to this too, so that we can peak at the right times). Let's ask ourselves why over every single season under Poch, we can pretty much plot a consistent curve between an average points gained differential between the first halves of the season and the second, to the point where our coming into form is almost predictable, to the point where we have hit heights greater than we have ever hit before. We do this because Poch and his team are so tuned in to the condition of the players as a strategic advantage, and how many minutes they have informs how much they can be pushed, that it has to be managed down to a seriously meticulous level, otherwise its not an advantage any more. So he's clear on rotation of full backs. He's clear on how many minutes he gives each player in a match, and broadly it works. It is a strategic choice.
And that choice will start being 'wrong' when we no longer start hitting the heights that we are now capable of hitting over the course of a season, where the short term potential benefits of abandoning the conditioning and tactical plans are not recognised, and neither are the long term ones where we can almost predict when our form will peak. Conditioning at this level is not an accident, and it is managed to a meticulous level. There is no surprise that Arsenal always have a run of 9 wins out of 10 towards the end of every season, because they are managed in something of the same way. So yes, we take a hit on maybe not throwing the kitchen sink at Southampton through subs, but we benefit from long term thinking and predictable runs of form. And it is this thinking that enables us to compete. It will stop being the right thing for us to do when it stops working long term, but over-reacting to short term results or dropped points is not the time or the way to be judging what is overall part of the strategy that has enabled us to compete.