Borussia Dortmund's business model of buying young players and selling them for profit has earned criticism from Bayern Munich executive Karl-Heinz Rummenigge.
Dortmund's player transfers to other clubs like Manchester United, Manchester City, and Real Madrid are seen as a loss for both Dortmund and the Bundesliga.
Keeping their best players is crucial for winning trophies, but players may still want to move if approached by another club or if they desire a transfer.