I suspect the big limits on payments migration is that many people live on credit. Someone else mentioned the future promise of FedNow. I'd expect that would

I suspect the big limits on payments migration is that many people live on credit. Someone else mentioned the future promise of FedNow. I'd expect that would be "any legal use is permissible" for legal reasons, but it can only replace debit payments at best. If you had a lender who worked atop FedNow, you'd reintroduce the problem of having a private party who is not legally obliged to serve all possible customers.