Those papers are not concrete plans to move their core processing network to ISO20022. The first one is just talking about 20022 in general, the second one refers to Visa DPS which is effectively a wrapper over their EAS which does speak 20022, but their core comms are still 8583.
I'm sure that Visa and Mastercard are very aware of 20022, but being aware of it isn't the same as having a concrete plan to move - actually moving _everything_ would take a very long time, there are so many card issuers & acquirers out there with old systems plugged into Visa and Mastercard that would have to be replaced.
FYI I actually built a cloud based issuer processor connected to one of them within the last couple of years - that was 8583 and there was no option for it to be 20022. We would 100% have taken it if it were an option.
> you get schema files and punch your programming button and generate a lot of the necessary code and then do the plumbing and call it a day.
I think that's pretty naive in terms of what parts you have to do in order to process card payments. Okay, yes, parsing messages is easier, you still have to deal with HSMs and all the crypto stuff, PCI compliance, all the logic for the various message types, scheme compliance, then the long tail where reality diverges from the spec (basically acquirers will send you any old absolute nonsense and you'll have to somehow figure it out otherwise your customers' card payments get rejected).