Every single Open Banking implementation I know also requires everyone to go through a useless certified middleman (eg. Plaid, GoCardless, ...) instead of letting people use the APIs directly
Open banking is slightly different, as it's more about account access (although with read+write access, you can kind of build it into a payment scheme as well, although it's usually clunky).
When you say rest of the world, what countries exactly do you mean? I'm from the Czech Republic and the process is also insurmountable for a regular company. You either go through a middleman or you can apply for a license (only 4 companies in the entire country ever got it and it costs upwards of $50k in legal fees just to file the application).
Can you just link us to the relevant pieces? I rather not search on my own and read wall street propaganda on why it's bad (which is what I'm finding and not interested in).