Alemar
This is pretty obvious, but the real question is what is the reason underneath? Why?
I think that I can perhaps answer this. In his autobiography ( not everything here will be verbatim so please allow some artistic lisence as I no longer have the book) he announced in 2001 and he says that the players basically downed tools. Despite who he was , and what he had achieved he says the majority of players knowing he wasn't there for much longer simply stopped playing for him. Then over the Christmas break he has a chat with Mrs. Ferguson and comes back and tells them "I'm not retiring." I think he then says something like, we didn't lose another league game that season and won the the league.
So if SAF with all his greatness loses the dressing room when they know he is no longer there for the long run, how hard must it be for a manager who is announced as the interim manager to get the players to commit for him ? I suspect that he has many different ways of doing things from the previous regime, tactics, training, video analysis, fitness, psychology and many of them may be thinking, " I can't be arsed with this and he's gone in May, and maybe I will ask for a transfer as the club's going nowhere anyway"
Some will be thinking well if those 5 aren't trying in training or on the pitch I can't be bothered either so let's just wander around and see not the summer brings.
I think announcing an interim manager was setting him up for failure.
I found this paragraph to be the most illuminating in the whole book. When they thought he was leaving they simply stopped trying and when he said," I'm staying" they went on a run and won the league.