Throughout the history of football, managers have made huge decisions, some decisions work out and some don’t and the bigger the decision the bigger the risk to the manager.
Managers have consistently picked their best players when they are unfit, carrying a knock or out of form. It is very easy to draw a list up of high profile managers that have done such a thing.
Just from memory, I recall England manager Terry Venables sticking with Alan Shearer who had gone something like 18 months not scoring for England and he came good in the Euro’s or Ruud Gullit dropping the same player and losing his job the very next day.
To this day Mauricio Pochettino maintains he did the right thing selecting Harry Kane for the Champions League final and how many players have been taken to international tournaments (not just England) that are clearly unfit, injured or in woeful form?
The reason, in my opinion, is simple, picking a player, especially one out of form, is the easier option, it is certainly less risky because some of the blame then shifts on to the player, drop a player and lose and guess who gets all the blame.
Basically, Mikel Arteta cannot drop Pierre-Emerick Aubameyang because if he does and Arsenal loses then all that blame is on the Spaniard, whereas right now most fans are asking what has happened to Aubameyang and some are even claiming he is suffering a form of Ozilitis.
Any other player showing such a drop in form would get dropped but they do not carry the risk that dropping Aubameyang carries.
Look at the Mesut Ozil situation, this is a player that created almost zero for years and finally, he gets dropped and when Arsenal cannot create chances some of the fans want him back ignoring the fact that he was utterly useless when he was in the team.
Imagine what the reaction would be if Aubameyang was dropped, it would be hysterical.
Arteta may not be the best manager for Arsenal but he is not stupid, he will know that even if Auba deserves to be dropped and others given an opportunity to step in, that the sack will soon follow if he took such a momentous decision.