Well, there is Real Time Payments, as it is called RTP by The Clearing House. (RTP is almost like FedNow.) However, The Clearing House is owned by a small number of banks. That's why only big banks use RTP. I heard about 50 banks use RTP, when 10000 financial institutions exist in US. This is also one of the reasons why majority of credit unions don't offer Zelle, as the latter is owned by top banks.

The bigger culprit is private entities controlling infrastructure, and these entities want their tax.