You have the highest reputation in a 3 person league. You need more and stronger competition, or you need to finish 1-2 every race, even then you probably will lose a little bit of rep.
Start talking to the rookies and find out how active and interested they are. It won't hurt for you to wait for the next batch of managers to be promoted. If you are truly concerned that there will be little interest from the teams in rookie, then it may be time to switch after your season ends
