I also have been selling for 9 years on ebay and I have to say that this is as bad as I have seen it...
I hate to say it, but a Cubs/Yankees or a Cubs/Red Sox World series would have been the best thing for baseball and cards sales... I mean, the D-Backs can't even sell their post season tickets to the game.
I am not ready to give up, mainly because I have too much inventory, but there has to be another angle to go at it during the slow times to boost sales.
I have resorted to puting up Rookie Lots of players who are left on teams in the playoffs.