Nope. They just need to provide "an API". Got a hundred banks? That's potentially 100 integrations you'll need to do - the barriers remain in place an everyone is happy.
On the positive side, someone could provide a library which covers these but doesn't require going through a third party. i.e. that library could provide a "single api" with none of the risks of picking an unknown third party. If that were done as an OSS offering you'd also be able to easily confirm there was nothing lurking in the library under the covers.
100% coverage might be quite time consuming, but getting most the market is not going to be excessively hard.