When the guy who gave the presentation asked for a show of hands to see who in the room thought this would work, every hand went up except one -- mine.
That was almost 25 years ago.
I'm thinking we're always going to be 25 years away from practical applications of these things. And it has nothing to do with technology, either. As I pointed out above, we've had the technology to do this for decades. It's all about cost, regulation, and legal ramifications of the whole paradigm of "self-driving" cars.
Nevada is currently permitting Freightliner to run their Inspiration trucks on the highway. These are test vehicles at this point.