Short-term negative-sum transactionalists are governing the US. Even if November stabilises things somewhat, the cat is probably out of the bag.
Trust comes on foot, but leaves on horseback. _That_ is why a well-integrated EU-based payment system is needed.
There are examples of other co-branded national payment systems out there (troy + Discover comes to mind).
If a European payment system (with cards, at a store) is to exist, then visa/mc will still want a piece of the pie by at least playing along to remain as a co-brand and taking their cuts from international payments.
So sorry, we do definitely get what this entails :)
They didn't just switch. They purchased Discover.
edit: added the "just"
It's free, their tech is great and their fx rates are more than fair.