Barca is also trying to do the same as elite European clubs who are currently intensively improving their squad. However with a modest budget, Xavi cannot do much to recruit star-labeled players. Taking advantage of Barcelona reputation as a big club can provide an advantage in the pursuit of players with free transfer status, like Gundogan.
They already have great players from last season, there is no need to make many transfers should they be able to compete in the UCL. The arrival of Gundongan on a free transfer is very profitable. Xavi just needs to make the most of the existing players, by training the European mentality. Because last season they couldn't work much to their maximum and failed in the UCL. Next season is Xavi's best moment, although I'm not sure Barcelona compete much until the Final.