In general, I wonder how Borussia Dortmund manages to remain among the leaders of German football with such tactics of the annual sale of their leaders. On the other hand, after all this, it is not at all surprising that Bayern Munich has been consistently becoming Bundesliga champions year after year for the past eleven years. And even when Bayern Munich seems to be handing the title into the wrong hands, as this season, Borussia Dortmund is not able to take this title and take the decisive step.
Dortmund management made this sale maybe they have a certain strategy for the long term and they did this a long time ago. if we think logically maybe this will be very detrimental to the Dortmund team because they always sell their best players and not think about the title they will get to prove that Dortmund can become bundesliga champions or better yet can get some trophies.
but back to Dortmund management which we cannot know for sure and can only hope that Dortmund will give their best for next season.