Haven’t no one advise them to stop doing that or they’re just after money in the club only. I remember Lewandowski was one their players they sold to Bayern Munich that season, can they ever imagine how good Lewandowski will become, a very great striker and the best in Bundesliga during his stay in Bayern. I hope they change their perspective and learn to keep players that are still valuable to the team.
But it is indeed a business for them too because if they don't do that then their condition will not be too good in terms of their financial stability.
Of course, losing this player will also have an impact on the stability of the club, but forcing a player to stay whose contract is about to expire is risky for Dortmund.
Now what they need to do is no problem their star players leave but not to the rival club is the most important.
Most of the peoples those are following soccer understand how Borussia Dortmund business models works mostly they bring new talent on cheap prices and after few seasons they sell them to top clubs with good profit which is their main intention instead of winning trophies they have huge profit in their system so same thing happen again even their last season was at this best but still they are not trying to keep their best players and try again for the title they are preferring profit.
Even losing player like Jude Bellingham is big problem for them but they will surely bring someone new in coming days and go ahead with their next target as well in Bundesliga we have two things Bayern Munich for their titles and Borussia Dortmund for their huge profit from the selling top class players to top clubs.