I think it depends on the EFTPOS plan that is available. In my business, we are stuck with one of the big banks because of the specialist hardware that is required. There are three different middlemen all taking their cut along the way through. Some of their costs are fixed, some are a percentage. My average transaction value is between $2 and $3, and my costs by the time we add up each mob taking a bit along the way from the device to my bank is somewhere from 20-30 cents, so as a percentage that is 10%. That's a far chunk out of my profit margin. How I react depends on the situation. At some sites, I add a surcharge, in others I roll it in to the costs and absorb the costs myself (which means those paying cash are technically paying more).

In any case, these are business decisions, and so long as no one is forcing you to shop where there is a minimum spend, you can decide where you will shop and businesses will adjust accordingly to the market forces. (I agree with @mattclarke that these minimums seem to be dying out.)

I am looking forward to being able to integrate blockchain payments systems into business to cut out costs for credit card fees. Bitcoin fees are no even more ridiculous than Visa and Mastercard on microtransactions, so it would have to be something like a graphene based chain.