I agree with you that your example is probably a rare one. Which is why I'm still searching for an answer as to how this is all supposed to supplant the card system.
The merchant may be very strongly incentivized to use Bitcoin because it cuts payment fraud to zero. This saves the merchant the direct cost of payment fraud, which averages 1-2% of revenue in the US (therefore up to 50% of profit margin in some industries). Note that 1-2% is an average -- some industries have higher rates of payment fraud, and they will therefore have greater savings.
As Bitcoin payments require no fraud prevention, they also save the merchant the cost of lost business from customers deterred by cumbersome fraud prevention methods, and losses due to legitimate customers who are rejected when fraud prevention gives a false positive.
Therefore, merchants will have the option of reducing prices for items purchased with Bitcoin.
This leads to a simple question: do there exist any industries where the merchant's savings could be big enough that they could reduce prices sufficiently to encourage a significant number of customers to pay with Bitcoin, while still earning a higher margin than they would from other payment methods? I think there probably are, but we're a long way from seeing this question answered by the market. Relatively few merchants accept Bitcoin, and many of them offer no special discounts.
Relevant news: http://gigaom.com/2014/04/02/paystand-takes-on-paypal-with-a...
As for the idea that merchants will do differentiated pricing for cards... couple problems with that.
First, it's historically a really tough case. It's generally not worth the risk of losing a sale. But let's put that aside.
Second, you've got the competitive landscape wrong. The Durbin amendment changed everything. Did you know that debit card interchange is now regulated down to 21 cents + 0.05%? And they come with some consumer protections and are "built in" to most bank accounts and all the infrastructure's in place. That's what Bitcoin or any new method that competes on price is competing with. So that narrows the opportunity to almost nothing.
Yes that's true, Wikipedia does say that, but please think about that number for a minute.
0.07%
With all the wailing and moaning we hear about credit card fraud and identity theft every day, does that figure sound plausible? Would anyone really care about fraud if the cost was actually that low?
Regarding the accuracy of that figure, I'll refer you to one of my previous comments: https://news.ycombinator.com/item?id=7506761
Certainly it's true that Bitcoin has none of the consumer protection features of credit cards, and that will be a major deterrent to consumers in many situations. It's also true that differentiated pricing isn't something that every merchant will just want to casually drop in.
As for the Durbin Amendment, you seem to know more about this than me, so I'll ask you a question: Since it was introduced, has there been any significant reduction in the percentage of revenue that merchants lose as a result of identity theft (card not present) or 'friendly fraud' (chargebacks)?
The bigger question here is whether bitcoin can actually improve on this or just change the type of fraud that happens. If for example it shifts the burden from merchants (who absorb most of it with cards) to consumers (who can never recover lost bitcoins) then it's not going to gain traction. It's got to appeal to both sides of the market.
It also has to be significantly better than the status quo. There are many markets where using Bitcoin currently doesn't have a significant advantage over the existing payment options, I think. In fact, I'm fairly sure there is often a net greater cost spread across both parties if they use Bitcoin, if you consider the case where someone exchanges other money for bitcoins in order to pay with bitcoins, and the merchant exchanges the bitcoins for other money.
However, and this is an important point, Bitcoin does not have to be suitable for all markets worldwide to establish a presence in some markets. In fact, it doesn't even have to appeal to every merchant operating in a market - just to some of them, perhaps those with the lowest profit margin. If Bitcoin is to succeed as a method of payment, then I expect a scenario where Bitcoin gains a small bridgehead in niche markets, which then slowly expands to some other markets.
Markets that suffer the largest burden of ID theft/chargeback fraud as a percentage of profit seem to be the most promising candidates for that bridgehead. An online merchant with a 4% net profit margin, who is also in a high risk market where they're losing 1% of revenue (i.e. 25% of profit) to fraud, might consider offering a 10% discount to customers who use Bitcoin, for example.
I'd guess the reasons that we don't see so this happening very often, so far, are: lack of familiarity with Bitcoin on the part of merchants, lack of sufficient volume to make it worthwhile to add a new payment method, and finally, some early adopters are still willing to spend bitcoins for ideological reasons or because they made an enormous profit by buying in early, so there's no need to offer those people an incentive.
Table of average net profit margin by industry, Retail (Internet) has an average 3.37% margin: http://pages.stern.nyu.edu/~adamodar/New_Home_Page/datafile/...
I don't actually think it will be of huge benefit to people like you who are happy with their credit cards. What Bitcoin will (and is already doing) is enable new applications and a new internet economy where location and real identity is no longer important.
(In this sense, I suppose I'm kind of agreeing with you, since I don't necessarily think there are any absolutely concrete examples of Bitcoin supplanting CCs. I think Bitcoin's greatest potential is elsewhere in untapped areas.)
That doesn't hold in the mail order or online world. Consumer protections are more important.