The only reason some cards are not accepted somewhere is because Visa-Mastercard are so powerful they force 3%-5% margins on transactions for merchants.

In the EU the just use bank cards. And since there's regulations the fees are lows and everyone can use it everywhere.

No... You have the option of any of 50, and they can all be accepted everywhere; rather than the option of only two if you want a chance of being accepted. I believe this is already law in the EU anyway, but there are few competitors to the big two.

What's law? That you have to accept all types of payment? Nope.

If everything has to be accepted everywhere, then there's no differentiation