Earlier quoted context omitted.
Of course, Bitcoin is also designed to charge a processing fee. This is currently optional, but it is entirely conceivable that this would change in the long run if Bitcoin ever sees adoption on a serious scale. This holds especially true given that mining awards will go down. Furthermore, services built on top of Bitcoin will have such charges as well. I don't think economics as a science has a consensus theory that…
You know the bitcoin exchanges are taking a transaction fee in the same way the credit card companies are, right?
I'm very much behind on this since you wrote that two days ago, but I wrote my initial reply in the mindset of "what if Bitcoin becomes more pervasive" - as in: it gets increasingly used as an alternate currency. But of course your point still stands for the world today, and that other world will probably never come anyway.