Now I may not be such an experienced bb player BUT a simple a way I've figured out to fix this IS: Depending on what league you are in, introduce sponsorship contracts. At the moment I'm in league 3. Earning roughly 20k a week with a full arena. A tanker however would be earning 100k a week, if I'm not correct.
Sooo, why not make a sponsorship contract which determines how much money you earn per game won, but not only that, but also how much money you will win if you make the playoffs.
Eg. In III.2 (random) team A earns 30k a week. Through the contract he earns another 20k per game + 10k for every time the fan favourite is played 40+ minutes (listed in the fan survey) therefore 50k all up and 80k per week. Team B however has 5 players, all of which are scrubs. He has the same sponsorship contract, although he is tanking so the only extra money he is earning is from the star player earning or the fan favourite. As an enticing factor for both teams, if you make the playoffs, you earn an extra 100k...
Newly promoted players will have larger contracts though. Simply because they have to adapt to a harder league therefore they'll be earning something like 80k in EXTRA money. Any flaws, or further ideas, let me know. :)