>Speaking of credit card companies: why do they exist?? Why can't my card just sign a digital request for transfer and tell the POS terminal to send it to my bank to be executed.
Because the POS terminal (or more likely, the payment processor) would have to work with thousands of individual banks. The credit card companies handle that complexity so that payment processors only have to integrate with a handful of credit card companies instead of thousands of banks.
There are standards, however making them "open" wouldn't change anything. You've obviously never tried to integrate with a large number of separate entities before.
I have not, I've just clarified the point of the parent in case you misread.
But now I'm curious, what are the challenges with having a large number of entities implement a standard? Is it "just" the shrink-wrap effect of having a few-initial or large players, is it getting the parties involved to even agree to the standard, or what?
You are talking about a many-to-many relationship here. Every payment processor has to ensure their system works with every bank, and vice versa. So the standard defines the data format, great. What happens when Payment Provider #223 has an issue communicating with Bank #16252? On an even bigger scale, who is going to maintain all of the necessary technical info for the parties to all interoperate? Who will handle fraud detection? Who will be liable for fraud that goes undetected?
Credit card companies handle all of that and much more in exchange for transaction fees.
Because the POS terminal (or more likely, the payment processor) would have to work with thousands of individual banks. The credit card companies handle that complexity so that payment processors only have to integrate with a handful of credit card companies instead of thousands of banks.