But he is already 25 years old, and in a few months he will be 26 years old, if Dortmund wants to make a profit in one or two seasons by reselling this player then Edson Alvarez must appear very impressive so that many clubs will glance at him and his market value will increase quite a lot, so I think this is just an ordinary Dortmund purchase to strengthen his team which is also not so good in defense because if they are good in defense they will not fail to win the Bundesliga, so if the goal is to sell back they will look for younger players at a lower price than they had to spend for Edson Alvarez, but we don't know for sure about that, because Dortmund knows better how to continue to profit from selling potential players.
If calculated from his age, he only leaves at least two more seasons to prove his quality at Dortmund and after that we certainly also know what Dortmund will do if the player reaches his peak. As usual Dortmund's target is not to win the bundesliga and even if they were serious about not selling their players they would have won it a few seasons ago. On the other hand, currently Dortmund still need one player in the LB position because Raphael Guerrero has just joined Bayern Munich and the position is currently still vacant for players who want to get regular minutes.