Do you really just use your bank's app to transfer money to anyone, though? Sure, here in Norway if I know their account number I can do that, but if I want to transfer money to a friend, I'm probably going to use Vipps because I only need to know their phone number. I consider Vipps to be a 3rd party app even though it's jointly owned by the major banks here.
Every country is unique, but the financial system in the US is, as far as I can tell, quite unique, in large part due to how large the country is both in physical size and population, combined with a governing system that decentralizes a lot of power (which means some changes are much harder to mandate vs what China can decide to do, for example). You have to understand some of these foundational differences, after which it makes much more sense why some things move much more slowly in the US.