This is an interesting article that points out the high cost and scarcity of Arabica beans. Some are adding the more plentiful and cheaper Robusta beans to their blends to compensate but that is causing dissatisfaction in the taste with customers. The Robusta bean has a more bitter taste and far more caffeine.
http://capico.blogspot.com/2012/01/coffee-roasters-are-experiencing-lull.html