Allegri position is indeed quite threatened at this time at Juventus and even many fans have asked management to evaluate, but it seems that management still really trusts Allegri to train the Juve squad until his contract expires, the lack of creativity in the midfield I think is the current obstacle for Juventus in every attack which they have built, besides that maybe the ancient tactics used by Allegri so far at Juventus may also be the reason for other teams to beat Juventus too easily, the length of time Allegri has coach at Juventus and the absence of a change in scheme allows the opposing team to know every weakness that exists in every juventus game.
Most of these "we didn't get the results we wanted, we should sack the manager" type of questions and actions do not really reflect on the step afterwards and that causes a little bit of a trouble. I am not saying that it should be an easy task, but it needs to be carefully planned for the future.
Like let's assume they fired him, who are they going to get at this point? Are they really sure that they would be able to get someone that would be as good as him, or even better? I am not sure that many exists, Tuchel is the only one I can think of and I really doubt that they could get tuchel, both because of price reasons and he would rather go to a bigger name club too.