Notice that this is entirely a regulatory problem. Do we imagine that entrepreneurs in the US can't produce the technology for a good payments system? That's not the reason. The reason is that anyone who wants to build it gets squished by the regulators captured by Visa and Mastercard because they don't want anything that would take away their cut.

Zelle made it through by having various limitations that make it hard for it to displace credit cards, and even that took decades before it happened.