Well, it was mainly because of this:
While this measure alone might not discourage tanking, a new initiative has been announced by fan clubs all around BB; fans have decided that they will not tolerate long losing streaks if team has the funds to prevent them and will boycott teams that don’t have at least one victory in each third of the season or suffer the consequences of the boycott, severely reducing ticket income! This means that ticket income might be reduced by as much as 50%, depending on current team funds (while poorer teams might not even feel this, rich teams will be affected strongly).
I have a few million dollars in the bank account, so if I don't win one game my fans will hate me. =O