The industry of payment cards is essentially an oligopoly of few companies that control the entire market(visa, mastercard, maestro and few minor ones).

This has been possible due to the way the things worked in the past. But now when we have internet connectivity everywhere and most banks have public APIs, why do we need to bow down to these few selected companies and play by their rules?

What would it take for this market to get opened up so new players could come in?

Essentially a payment card provides a way to send money from one bank account to another, not necessarily in the same bank, via intermediary. This intermediary is able to do so because the banks themselves are connected to it. Paypal on the other hand is the reverse of this - it is an intermediary that has accounts in all the banks on its own. Which could be taken as brute fore approach.

With banks now being forced to have public banking APIs, how do you think we could finally get rid of these few big players and enable smaller companies to take part in this business?

I guess without to cooperation of the banks, this is where any attempt would stop. Plus the user base of the physical cards. But everybody has a cell phone and Apple Pay and Google Pay are now quite common, so the piece of plastic is no longer needed.

Hence the question - what do you think it would take to finally get rid of this oligopoly for good?