> the U.S. the Federal Reserve is already planning to support it

The U.S. has a real-time payments system. (One of the oldest in the world.) It's called Fedwire [1].

It's artificially kneecapped–Congress set a minimum fee of pennies on the dollar and many banks charge retail clients $10 to 35 for wires. But the rails are there and used and understood.

(Detour: my "abolish the penny" issue is expand Fedwire's market hours, enable it on weekends and remove all Fed fees for wires under $250,000.)

[1] https://www.federalreserve.gov/paymentsystems/fedfunds_about...

It’s only for small money transfers, up to $25k last time I’ve looked at it.

For bigger transfers, the $10-20 fee for a fedwire is no longer much of a factor, so people will just use that.

> the $10-20 fee for a fedwire is no longer much of a factor

That is almost entirely your bank charging a mark-up.

The Fed charges its members between 3.3¢ and 84¢ per wire, depending on things [1]. (It can go as high as $1.20 for a $100+ million wire from a bank that handles fewer than 14,000 wires a month.)

My bank, for instance, doesn’t charge anything for wires.

[1] https://www.federalreserve.gov/newsevents/pressreleases/file... page 34

Which bank do you use that doesn't charge for wires?

Not OP, but Fidelity is the only financial services firm I'm aware of that doesn't charge inbound or outbound wire fees (exceptions apply if you're a high net worth individual at other firms).