Re: Horse carts vs delivery trucks again.
"Who's going to write the code to allow the AI in the trucks?: humans."
A FEW humans, not several thousand. Furthermore, most of the jobs are already filled. So Zero opportunity.
"Who's designing the electronics (Chips, circuits, etc.)?: humans"
Again, A FEW humans, not several thousand.
"Who's doing the maintenance on the trucks?: humans."
Don't be so sure. Standardize the robotrucks and you can just put them through automated tunnels.
"Who's issuing the instructions?: humans."
To a lesser and lesser degree. As more and more orders are processed electronically, they become more machine-readable, reducing the human angle. Remember, elevators once had human operators. See any now?
"There are no longer people who come around in wagons to empty the outhouses and chamber pots."
Thanks to indoor plumbing. But go out into the sticks where they don't exists and you'll still find the odd outhouse.
"There are no longer people who come around in the morning with large urns of fresh milk to fill people's mil pails."
No, they come with pre-filled bottles. The milkman still exists in firms like Oberweis Dairies. That said, I still think they're vulnerable to automated deliveries.
"There are no longer people who ride on horses from coast-to-coast in relays to deliver mail."
They just drive trucks instead, so they still exist for now. And if you want a hurry, you now have pilots, who for the moment are still human.
"There are no longer people who come around with large ice-blocks to fill ice-boxes."
Maybe not in homes, but there are still ice chests in stores.
"There aren't many people who come around delivering bottles of gas for household gas usage (stoves), it's mostly all piped in now."
Maybe not, but the tanks still exist, the trucks still exist to transfer them. They just go to store cages instead of the home. Sort of a compromise to keep costs down. Plus, the delivery still exists in certain areas where the infrastructure's different.
"Things change. Adapt or stagnate."
Don't leave the proles behind. History shows that dead-ended proles with no food on the table tend to get violent.