How come the US -- the biggest economy in the world, and home of the most sophisticated banking sector on the planet -- is still not equipped with such a system?
Because, as pointed out in other comments, the United States pioneered electronic finances when the rest of the world's banks were still settling their accounts at the end of the day by dragging cartloads of paper money and gold bars from branch to branch.
None of the “you’re welcome” snark changes the fact that there is inertia and a lack of intent to disturb an already existing payments infrastructure for a better one.
Because, as pointed out in other comments, the United States pioneered electronic finances when the rest of the world's banks were still settling their accounts at the end of the day by dragging cartloads of paper money and gold bars from branch to branch.
You're welcome.