The loss of prestige from the sale(s) would also contribute to that. I'm pretty sure Suarez would come here if we had the money to pay for him now, with the chance to play with players like Tevez, Vidal, Pogba, Pirlo etc, but not if we sell them to buy him. That's just recycling. As it is we don't have the money and probably never will be €60m for a player.
All this talk about the values of Vidal and Pogba does make me smile, considering how much we paid for them. That shows you not to be obsessed with paying big fees, we develop quality and always have.