I don't think its autonomous cars that will kill of the Manual and Automatic transmission , I think its electric cars that will kill off everything that we know about cars . Once these become more mainstream , the charge times decrease, manufacturers start adding more models to their ranges and the Distance range extends to over 700kms , the petrol and diesel engine with its gearboxes will be dead .
I spoke to an I3 owner a few months back , he was an older chap, and he said the only reason he still has a petrol engine car was for long distance driving, his now thinking about selling the car as he worked out that it would be cheaper for him to hire a car for long distance travel then to keep his petrol engine car , once he got used to the way that electric car worked , he find it very difficult to go back to a normal petrol engine car, He tells me its perfect for his daily driving needs . If manufacturers improve the above , and the older people get over "range anxiety" (Younger buyers wont have this issue as it would be a norm for them if range improves) I don't see much of a future left for internal combustion engines.