IIUC the EU basically had to force banks to implement this via a mandate. I don't see "business friendly" US lawmakers doing the same anytime soon. The joys of the Free market™!
I mean, yes, it was mandated, but I am decently confident a usable system would have emerged one way or the other. In Germany we had a standardized API for online banking (HBCI) just because banks agreed it would be reasonable to do that.