Yeah, well, it was a general point. There will always be exceptions - in Fergie's case he bought and sold players over a period of 25+ years, so it would be odd if he was spot on every time.
The reason this one stands out is obviously that the player in question is a record signing, bought in his prime, presumably as a key player - and now looks to be moved on after ONE season. It's rather extreme, at least in a United context.
It's virtually an identical situation from the clubs point of view to the Veron transfer. Huge sum of money on a central midfield player who was never in a million years going to fit into the managers central midfield plans. Both creative risk takers who liked their freedom to express themselves but both managers unable to afford them that luxury in their system. Badly researched. If you read Fergie's book he said that when trying to play him in midfield he'd show zero discipline and wouldn't stick to any sort of game plan. He'd ask him to operate in an area of midfield and he'd turn up at right back or left wing looking for the ball.
The only difference is that Di Maria is a special kind of prick that can't even be arsed to try and fight for his spot and prove his worth so his move is happening a year earlier.