"What will happen is that the richer part of the world will fight wars against the poorer part of the world where they won't be able to afford the machines."
This is the principal reason why "drones, OK, land mines, not OK." A land mine is a drone that waits for you. It is simple and cheap. Any armed group could afford them. Drones require high technology, among which satellites to relay video links and commands, etc. The "human in the loop" is just a bureaucrat rubber stamping, in real time, decisions made by a de facto autonomous weapon.
A drone also isn't there thirty years later when the country has a different name and a different form of government and an eight-year-old puts an errant foot where there was once a target designated.
This is already happening.