The club have kept the fans informed. Martinez has publicly made clear a few times his strategy and expectations for this window. But, if he or the club were to say "we're going to buy player-X", then that player's price immediately goes up a few million. The moneybags' clubs like to feed their egos by announcing their targets and then buying them, as if they have the power to get anyone they want, but they pay over the odds when they do that. And some (thinking United) make fools of themselves when they fail to bring in their targets.
If United had kept things quiet, I'm sure they would have paid 3m less for Fellaini. Having set expectations in public, however, they either had to pay us more than his value or let everyone down.