It will come but not for a long time
autonomous cars will arrive one day but not for a very long time so long as they have to mix with the human controlled ones.
I personally believe that what is driving the car manufacturers is the "but they are doing it" mantra and they don't want to get left behind.
some aspects are in some cars now such as auto-braking (although that TV advert has small print of < 5 mph!), and there has been talk for years about cars having a 'mesh grid' to communicate to those behind them that they are stopped just around the bend and you had better slow down from 70mph like kinda now....
So just as those top of the range features on the most expensive cars filter down to the cheaper versions, so bits of autonomous tech will slowly be added to existing *newly* purchased models. As for your 70 year old classic car....tough.
Given the current track record of car manufactures on IT security it could also be a car crash nightmare