> It’s not hard, it just requires you have politicians capable of dodging the huge piles of cash MasterCard and Visa throw at them whenever talk of breaking the duopoly hits the table.

Ignoring the difficulty of avoiding lobbying money, yes, it'd be difficult. This is a large scale financial change and there are always, always loopholes that will come, not just from politicians who make those because of lobbying money. With how giant the economies are, and how often these cards are used, it isn't a simple move at all.

Look at credit card chip readers in the US. The amount of backend equipment change it took to get something "that simple" in action was a lot. I'm not defending them for it not being quicker, but a move like a duel card is absolutely difficult.