Until what? 100% replacement of human-driven cars? Being rolled out for areas covering 50% of the population? Where is the goal line here?
We are already at the stage of commercial operation, with rides available to the general public - even though only in a few locations.
Sure, it's far from being everywhere, but why pretend that progress has stalled, when it clearly hasn't?
They possibly are (or at least have people doing research), it's just not very good (yet?) https://aimodels.substack.com/p/apple-is-working-on-multimodal-ai
Remember the early days of Apple Maps?