AIUI, the paper giro was a direct interbank transfer decades before ACH was even a thing. They were widely used in Europe but never introduced in America. That

AIUI, the paper giro was a direct interbank transfer decades before ACH was even a thing. They were widely used in Europe but never introduced in America. That might be part of it. Also, America has a lot more banks per capita than the rest of the world. Until the 1990s banks weren't allowed to operate in more than one state, and although there's been a big wave of consolidation since then there are still a bunch of tiny banks in out-of-the-way small towns that are very set in their ways and don't want to spend money on newfangled technology. In the rest of the world, you get the major commercial banks on board, and maybe the dominant network of savings funds/cooperative banks/credit unions, and that covers just about everybody.