Whether Barca has the highest revenues, or is just at about the same level as the other best-grossing teams, there is going to be so much money that money will never be the problem. Using it smartly will be the challenge. Using it smarter than RM or Man U is not hard to do.
I think Barca's major financial decisions recently have been excellent. They spent big, really big, for both Neymar and Suarez, and it is already clear that they got bargains for both. Pivotal decisions like these outweigh dozens of minor deals like Douglas or sales of squad players.