It is not about having targets but bringing it to reality is what matters. Barcelona don't have funds and they want to buy quality players but they don't want to sell players to have the finance to bring in these set of young players which they want.
In terms of Barcelona selling some of their players to get new ones, we should also consider the fact that majority of there players we are expecting them to sell may not worth much on the market, so perhaps before they could get one important player they must have selling up to three or four players before they could raise such amounts of money, so actually I believe that is one of the reasons why the club is finding it difficult to sell there players because right now apart from there first eleven I don't think their other players will probably worth much, so perhaps they must have been feeling that instead of wasting up to five players to get one experience player they could as well wait till they are financially stable before making any decision.
actually Barcelona should try to get rid of some players who didn't contribute much to the team last season,so that that way they can have enough money to regenerate the team today, De Jong and Lewandowski are the players with the highest salaries at Barcelona and they still have a selling value at the moment, but wouldn't it be better for them to be sold by Barcelona to be able to reduce the burden on the club and use the money to buy other players, apart from that De Jong and Lewandowski can no longer be expected because of frequent injuries and his age is no longer young.
What you said is actually right by getting rid of most players but the question still remains that how many players would they sell to raise up the kind of amount they want because currently not all the players in Barcelona are worth that much in the market, so for me I think the best way is not to sell many players but instead selling two or three players should be okay than selling a lot of players because they would be at lost by selling players that should be Worthing a lot in the future, so at least if they sell three players they would use that money to add up to there existing ones and utilize it very well. However in the case of Lewandowski I no that his market value is still high but I think Barcelona has not really seen a good replacement for him.