#1 The Money
Oh yeah, this old chestnut. In the game of football, you either have a ton of money to splash around everywhere or you die.
Bayern Munich are officially the most supported club in Germany, an international brand which generated the third-biggest revenue of any club in the world during the 2013-14 season. It’s pretty hard to compete with that.
While the rules for ownership in the Bundesliga restrict them slightly, it also holds back their rivals in competing with their swelled budget. It means they attract the biggest stars, like James Rodriguez from Real Madrid this summer.
In the end, this is probably the biggest and most difficult hurdle that Dortmund simply can’t overcome. When you’re already established as that global machine that even non-sports fans recognise, it will be almost impossible to top them financially.