The playes have to declare that they feel good at the club that pays them in the present, that's public relations stuff. The problem isn't that the top players don't want to join us (they would probably walk on foot to Camp Nou to put their names on a contract with FC Barcelona), the problem is that we have to reach an agreement with the clubs that have those players under very tight contracts. Settle with PSG (Marquinhos), Roma (Benatia), BvB (Hummels), Porto (Mangala) etc. and the players will be ours. Don't reach those agreements, and we won't sign anyone.
It's either you outsmart these clubs which find and buy good players and they make them even better, or you pay the top money they ask. But since Zubinepto can only outsmart himself... I'm pessimistic. Just pay big for a world class defender and let this be a harsh lesson for the future: you don't let anyone know you're desperate to buy a CB before you buy it. That's just like shooting yourself in the foot.