Ferguson sold Pogba and brought Scholes out of retirement. He kept Rio around long after his use by date. All he was good at was getting rid of players who challenged his ego or authority.
Keeping Toure is an inspired move IMO and will make it more likely that we will land Pogba.
This is different though. Pogba was a player lost, not a player Ferguson consciously wanted to sell. They just didn't do enough to keep him. I am talking about the right time to make a conscious choice to sell players and both Ferguson and Wenger have done this very well. Not perfect, but players like Van Nistlerooy, Henry, Adebayor (attitude not age related). Selling while there is still value. This is most likely our last chance to get an 8 figure fee for Yaya and use the freed wages on a player(s) to build a new cycle. We'll still have plenty of veterans. Yaya is a quality but declining player who even at his very peak was exposed in the high tempo European games. Just remember Gundogan and Bender making him look second rate. We face the possibility of having the most expensive squad player in history if his deterioration accelerates and we're stuck with him until 2017. Or worse, feeling obligated to play him when he declines because of his wages and reputation.