You're going to have to do better than that. Not only is there no proof, but merchandise sales come from star players, big signings mostly. Are you suggesting that the Bills fire Jauron and all of the sudden people started buying Bills mugs? It's ridiculous.
I'm sorry, I usually like what you have to post, but why are you buying into this? Merchandise sales wouldn't spike at all because of the signing. People aren't renewing season tickets yet either, until after a big time coach is named.
Also, if you're going off the "money theory"...no merchandise sales would replace the money lost in the firing. If anything, this move netted negative money for the Bills. Look, it's just no a possible reason. It's a cute idea, but nothing more.