Why should Dortmund continue to buy players, because if Dortmund have got players to put in the positions left behind, and Dortmund still have money in hand then it is indeed their business. After all, whatever kind of players are in the Dortmund squad, in fact when the season starts later, of course Dortmund will still be the shadow of Bayern Munich in the upper zone in the Bundesliga standings. So yes, I personally don't really care what kind of players Dortmund have each season because in the end Dortmund will be able to sell the players they have at a higher price.
That's right, Dortmund is a smart club and regardless of how many players they want to buy, they will still be able to manage well. I don't think anyone is surprised by Dortmund's cunning and they have been very consistent throughout season and season to continue to make money from the players they have developed so well in the team. Maybe the problem is that Dortmund will not be able to win the bundesliga title and that is their harsh reality every season. In addition, Dortmund is the best star player producing team so far.