Computers ARE orders of magnitude harder to use than cars. A car has (at the simplified level) a single wheel that goes either left or right and 3 pedals. The hardest concept relating to hardware is what a gear is and why you need to shift it (among a few others).
It is correct though that software CAN be more simple than that in their use. Those pieces of software tend not to solve complex or any problems in our real world though.
When it comes to 'coding as literacy' this has not much to do with using a highly simplified UI. It has to do with the fact that if I want to use most of the features of the machine we call PC, you HAVE to be able to program.
Sticking with the car analogy my kid can have great fun if I show her how to use the horn in the car. It will not allow her to do anything meaningful with the car (getting from A to B). All she can do is use the car as a toy.
I agree with you on the core problem though. Things are abstraced away from everyone in our daily lives in such a way, that people sometimes are unable to be 'precise'. By that i mean the ability to fully describe a problem and formulate an executable solution. I personally don't think programming is the solution to that. Personally I learned that concept in school in philosophy class.