It's like the Carroll saga isn't it. The whole world knew it was a bad deal, but they bought him for 35 mill Why did Barca blow their whole budget on Neymar!?
Neymar is a top young talent. And considering the interest from rich clubs, he would have cost that much or more for any club.
That said, I disagree with his purchase if it meant blowing all transfer money for 1-2 years. For that much money, Barca could have got 2-3 top first team players. Neymar plays in an area where Barca already has plenty of players, and plenty of up and coming talent. Even if Neymar is deemed to be a "must buy" purchase, then, Tello, Pedro or Sanchez should have been sold to generate money for defenders. Players like Rafinha and Delufeu are coming up, what is the point of having so many players of the similar ilk? Again, Song or Mascherano should have been sold to generate money. Finally, Thiago should have been kept.
Barca's terrible transfer policies for years have not strengthened but weakened the club. So much money wasted on players that did not improve the first team, and right now, there are gaping holes in the first team. A great coach has to come in and make the big changes Guardiola did to wake up this team. Like in the latter days of Rijkaard, the team has been underperforming.