Its always been in the policy of Dortmund to sale off players often, except for last see, they have sold off players almost every season and they do it at almost every transfer window openings. Dortmund looks to me like they are mainly about the business of making money and occasionally get to win trophies, interestingly they sometimes even make more money than the team that actually got to win the league title at the end of the season.

Las champions league, they made some good money of the champions league both from the funds they got findings second and that which they got form their players transfer, personally I even love the fact that they are making money even without having to really win trophies but the disadvantages is in the fact that they are going to often loose good quality players because they are not keeping them long enough, a lot of the recent to good players across Europe are mostly one who where groomed in the Dortmund team before they were sold out.

If these players where still in Dortmund, the chances they will win more trophies will be very high but they are not going to be able to make a s much money as they are doing, few season ago, Bayern Munich won the bundesliga title but it turned out that Dortmund still had the most money made in that season in the German bundesliga. Keeping the teams purse fat while the keep grooming good breeds of players have been Dortmuns technique over the years and it has effectively worked for them.