Honestly I don't expect much from Borussia Dortmund if they still behave like this (only making money from selling players). Even if there is a statement from them that they want achievement, I will laugh at that. What they need to do now is to improve the team first and not to be too greedy with profits.
Actually they have no intention of selling their star players, but any player whose name has been on the radar of big European teams will find it difficult to refuse requests and players will do anything to get out of the club, but the club certainly doesn't want to lose players for free, and they will hear all incoming offers.
Your all statement is completely opposite of what happening in Borussia Dortmund they are buying youths and then developing them into quality players for having their high profit, and surely it's a big business which is happening here for many years and just because of this Bayern Munich is dominating power in Bundesliga.
Currently, they have two players which are going to be biggest in next few years, and they are going to have millions of euros from their sell as right now Bellingham is under radar of Real Madrid and Liverpool and both already have inquiry about this player, but they are not in hurry about this player they will sell him in next two years with very good amount.
But in this season, first time after selling Haaland they have invested good amount for few quality players but sadly now Haller is ill and out of game for two months, so they are looking for possible replacement but nothing good happening which is going to be trouble for them.