The Future That Never Happened

Cover story in Wired, Aug-10 .
We still don't have, Laser Guns, Food in a Pill, Robot Servants, Nano Technology, Fusion Power, Quantum Computing ... and Self-Driving Cars.

The reasons are manifold, from technical or economic barriers to the fact that some ideas have never been positioned in any demand landscape (do they relate in any way to how people behave, their needs, wants and frustrations) and if, reframe an opportunity space, looking into it with the eye of potential customers, markets and industries.

Self-Driving Cars. To traffic-weary drivers, it sounded great ... Cars could drive closer together, increasing highway capacity and fuel efficiency while reducing accidents .. Prototypical demand-first innovation?
I also think it is not too hard to make vehicles that automatically adjust their speed and path to the traffic "neighbors". But it might require a lot of pricey  road sensors.
However, risks are another concern - imagine the vehicles, that behave like swarms, "panic" and turn into avalanches ( Starling Flocks .. ).  Imagine the lawsuits after mass-accidents ... So let them be restricted to 50 mph? Sounds not so great then?

This is what comes in my mind, when I think of high-frequency trading running data feeds into black boxes containing some algorithm that makes local decisions ....  that might become horrible in interplay? 
Is it the future that already happened, but should not?