You know the cultivation of humans in the film Matrix?
Now that is more ideal.
An architectural complex as big as a city where an AI manages everything (reproduction, disposal, etc.).
In the astral instead something akin to 'xian hell', where they can exist waiting to be reincarnated in this giant factory, this can also be run by thought forms, or various employees.
They will be micro-chipped in the brain and have a tracker and a 360-degree monitoring system, in case they need to be relocated for X project.
In the meantime they can have digitally induced visions where they will experience their worst nightmares, again and again, until they die.
After death, another life.
Various useful materials can be extracted from this factory (many of which will be used to feed the next generation of slaves).
Once a year we can have Hunger Games, or we can also organise battles, like those in the coliseum.
Personally, I wouldn't mind investing time and resources in eternal punishment of the enemy.
Sending them to an asteroid or against a star is a total waste, as well as an insult to all the victims of the enemy.
We can have more fun this way.
Back to the main point, I am not a big fan of cars, I see them as old tools, like the wooden cart with the horse.
I see in the future a world where people will be able to move around without the use of roads (with vehicles similar to small flying saucers for 5-10 people).
The roads will be mainly pedestrian, with some exceptions, and outside of that there may be rails for super fast trains (more for goods/materials).
Do I want 2800 slaves supplying my Mercedes Benz?
Right now I say yes, but in the future they will just be a danger and a useless thing.
They may be slaves, but of a different category.