Dortmund is purely a business club and it's not surprising when they can develop young talents, so if there is an offer from a European team who wants to make up for it at a fantastic fee, Dortmund will let the player go. But indeed the competition between Dortmund and Bayern Munich is endless even though Dortmund always loses its talented players every season and I think it will continue to happen if Dortmund still uses its mindset to always sell the players needed by the team to win the Bundesliga title or other competitions.
Dortmund is like a temporary place for young players to develop their talents, then after that, they will leave. Selling several of its star players at fantastic prices. The management said this was a compulsion that was issued in order to save the team's finances. In my opinion, this is good and there is nothing wrong because they will get a lot of benefits from this decision, but on the other hand, this habit will make it difficult for them to compete with other teams, especially with Bayern Munich. Because this will cause them to experience fluctuating performance every season. I hope one day Dortmund can change their transfer policy, and keep the talented players they have because after all this is in the interests of the team.