As long as Barcelona cannot clear the problem of financial troubles, they are not going to be able to bring in the players that the coach actually wants. And if they do not bring in the players that he wants, he is not going to be able to bring in the performance that everyone wants. I would not say that he failed to achieve such and such. Because the main priority was La Liga. And that thing is what they had made a target, Barcelona actually achieved. It will be interesting to see how Barcelona is going to perform in the Champions League. It is sure that they will need new players because with this squad Champions League is not winnable.
Barcelona will not be able to buy the new player is its financial problems with the club will not be solved. The problems are even some players are not interesting to leave from barcelona like ansu fati. I think that barcelona faces very difficult situation right now.
It's caused by if the club needs to use more effort to make sure it can raise around 200 millions for the club to comply with FFP. Barcelona will not be able to buy gundogan if ts problem will not be solved.
Barcelona's complex financial situation has left Gundogan in uncertain waters as the club cannot guarantee he will be registered under La Liga rules. According to some estimates, they need to raise somewhere in the region of €200m (£176m/$215m) in order to be able to register a few current players on new deals and make new signings.
https://www.goal.com/en/news/real-madrid-joselu-signing-newcastle-stoke-flop-espanyol-spain/blt68236b24ca36591fThis puts the club in a very difficult situation. Even though busquets and alba have been leaving from the club and it's not even enough to make the club can comply with the regulation.
Barcelona needs to sell more players as soon as possible or it will be missing the time to rebuild the club as preparation for the upcoming season.
Busquet's position was really important. Barcelona has no capable player to replace him temporary.