I think I said this before, but they didn't lose the title in the last match at home, they lost the title in a dozen of matches they should have won or tied before the last match was played. Dortmund is just not good enough and it has been like that for a while now. They have good weeks and then it looks as if they were able to break Bayern's dominance, but then the disappointment is so huge that nobody can trust their eyes what's happening. The last game last season was only the tip of the iceberg. The whole drama enfolded over the course of the whole season.
The present poor performance from the Borrusia Dortmund, they deserved it because they derived more pleasure and making enormous profits from selling their key players other than aiming to winning major titles. Last season would have become one of the good moments that would come from the players and the team's supporters, but the team choose to ruined it by losing their last match that would have settled the difference between them and Bayern Munich who was also the exact same points. Dortmund have to stop selling key players to other elite clubs and decides to stay firm and build their club surround these incredible players.
It's something they have to accept when they are still practicing habits that are actually not good for them in terms of the game. For business, obviously it's something that is very profitable for them, but they should also be more able to balance between business and titles. If they want to and they can suppress their habits a bit more, I'm sure they'll be a much stronger club than they were last season. And I would say they would be on the same level as their main competitors, Bayern Munich.
But as of now it seems that the management is prioritizing profitable business over titles. I won't talk about bigger competitions like the Champions League, but at least they can provide fierce competition in the Bundesliga and can stop the dominance that Bayern Munich has had until now. Bayern Munich are too comfortable in the Bundesliga, and before the league starts we can predict who will be the champions.