Barcelona is just lucky that despite their financial predicaments, they still have players who are loyal to the club and are doing perfectly fine if not it wouldn't have been easy for them and moreover, the La Liga they won last season is a good motivation that will enhance their performance next season so even if they don't sign much players due to their financial constraints, they can still manage with the present players and maintain a good form in the La Liga and the Champions League. However, the club's management really made regrettable financial decisions in the past, look at FC Barcelona now, regardless that they won the La Liga last season, it didn't even change anything in their financial system.
Barcelona are a big club and a one with rich history it is normal that they will attract players to join them just like Real Madrid. Their finances might not be stable but they have improved certainly it is a gradual process and I believe they will return back to old status.