The thing is Dortmund is a very successful club when you think about the business that they are doing. Let me rephrase, they are not a very successful club when it comes to achievement. But they are a successful club when it comes to earning money.
Because they bring a player forward who is not relatively known. And they make him a really good player who can certainly attract some really big clubs. In the end, they sell him for a huge profit. Thats what has been happening in Dortmund for a long time. So, they have two options. They can continue making money by doing what they are doing. Or they can change the way and actually go for achievements.
In breeding players Dortmund are very good at it. This is the only strategy Dortmund use in making money and it is workiing for them. If Dortmund can make plan and be serious about winning trophies it will also help them to generate money too.