The article claims big banks lobbying with their own competitor to FedNow delayed the rollout of real-time payments, according to those industry officials. But another factor I want to point out is that the USA has more small banks (and, I assume, credit unions) than any other country on Earth; affecting the ability for the network effects of a real-time payment system to take hold.
"The U.S. has more than 4,000 small banks. That's more than any other country in the world and more than all of the small banks in the entire European Union combined."
https://www.npr.org/2023/05/04/1173488958/silicon-valley-ban...
I am a member of one of the 20 largest credit unions in the US but they only allow to receive FedNow payments. Not send them. I am assuming it is expensive to setup and many small financial institutions may not be able to support it for years down the line.