Well buzzerbeater is not a copy of the actual basketball game. It's a game engine which simulates various things which are calculated with randomness. And buzzerbeater will never be an exact copy of the real basketball.
The fan survey has a formula with the help of which it calculates the happiness of the fans and based on this you fan will come to your games. You can't put logic in this calculations because the game engine doesn't know about logic.
Well you are not the only who complains about this problem that's sure.
In order to calculate your arena prices correctly you may join the offsite there is the possibility on calculating your ideal prices.
http://www.buzzer-manager.com/gestion_salle/The reason the numbers drop are various, but i think he main problem is the majority of managers fail to understand that buzzerbeater is not an exact copy of basketball and that the way to success is a marathon and not a sprint