A major block to this is banks. If a party want to pay from or receive to a bank, even when technical stuff is in place, the bank can put up a stink in many ways for many reasons.
Obviously the service cannot be a new idea, it is basically an exchange (though I would like automatic transfers), and if this does not exist I expect the real reason is the banks.
By automatic transfers I mean that from the user's perspective it is important that the money goes as fast through the "automated exchange" as possible, it should not hold money at all