In the market of payments, all banks compete with rather similar products. They make money of it in (a combination of) three ways - 1) direct fees; 2) "float" (interest earned on money 'in transit', low currently because of low rates, but huge money in other decades); 3) selling other products (credit, etc) to people who also need your payment services.
If you offer a faster and cheaper way to settle payments than your competitors, you'll be able to gain a lot of lucrative corporate customers.
However, if all of the major banks offer a faster and cheaper way to settle payments, then they all simply earn less in fees and also have to pay for developing a new system. This is a loss-loss situation, so it's going to happen only in face of strong competition by other payment systems (in which case they can near-immediately lower prices and increase speed to undercut them, while still making profit) or by regulatory means - e.g. the SEPA-payment legislation in EU forced many inter-EU payments to become much faster and cheaper than before.