Sums it up quite well. In the 1989/90 season almost everybody wanted Ferguson gone - but its a question about what to consider early in his United-career. His first season in charge was brilliant - but as you Point out, it all fell to pieces when Ferguson kicked out the old experinced players and replaced them with Ince, Pallister, Phelan and Wallace (Webb was injured)
What a lot of people don't remember is that Ferguson basically sold his entire squad from when he first took charge and replaced them with new players and youngsters:
He kept Robson, Gary Walsh and a young Clayton Blackmore - I think ever other player who started the 1986/87 season was gone when the 1989/90-season started. So in 2.5 years he let 25 or so players leave the club because they weren't good enough, too old, too disturbing to the rest of the squad or too injury-ridden.
And he replaced them with strong characters, strong leaders and players who never were injured - Bruce (leader/never injured), Ince (almost arrogantly confident), Phelan (leader/never injured), Anderson (leader/never injured), McClair (never injured), Hughes (leader/never injured), Irwin (reliable/never injured), Keane (leader/never injured)
You can see that OGS i trying to copy this - by signing Maguire, Fernandes (leaders who never are injured - strong personalities).