Dortmund management must change their attitude if they want to bring the Bundesliga title in the coming seasons because if they continue to sell star players, it is possible that Dortmund will fast for the title for the next 5 seasons. 10 years is quite a long time but Dortmund have always failed to break Bayern Munich's dominance in the Bundesliga.
Why change dortmund's attitude? There's nothing wrong with it. The only problem is on the DFL itself by preventing the clubs from getting more investment from investors. Dortmund was doing it caused by it's not a rich club. It used the money to sell its player as a way to keep its financial better. There's no way that can be done by dortmund other than it caused by the income from playing in bundesliga was not enough to pay all the expenses.
DFL was blocking investors from taking a part in the club..
In the bundesliga, only bayern munich is the most consistent in defending the bundesliga title because other teams are not able to do much because the depth of their squad is relatively dominated by ordinary players but in the depth of the bayern munich squad they are able to present many quality players.
It's caused by bayern was the only team that consistently buying good players from its competitor. Destroying dortmund from buying its good player has become the main strategy for bayern to always consistntly winning the trophy for more than 1 decade.
The only problem was in DFL. If DFL will give approve for the investors to put their money and bayern will be rarely winning the trophy again.