Every rifle takes one person to wield it; one more person that might decide to turn that rifle against the ruling class. A drone swarm is worth ten, a hundred, a thousand, ten thousand people with rifles, capable of being controlled by one person issuing high-level kill orders. The tyrants of the future won't need to risk arming "the proletariat".
There are still horses. Probably more than would breed naturally in the wild. There's less horses now than there used to be because they were bread specifically for their economic utility. Humans are not bread for their economic utility. The amount of humans there are is pretty natural, given the available technology and infrastructure. There's no reason to think there would be less if they contributed less to economic output if the output doesn't decrease.
If you want to compare people to some other animal why not choose dogs or cats? They have no massive economic utility now, event though they had some in the past, yet they still thrive, even better, just because infrastructure and total economical output allows it. Their is even a part of economy dedicated specifically to their needs.
I think being pets of this civilization is something humans might realistically aspire to. I'd say it's immensely better role than being its workhorses.
If you squint hard enough, luckiest of us are already living the lives of pets of the civilization, where they don't have to work at all and the machines made out of money, legal documents, devices and other people take care of their every need, within limits imposed by the machine. None of those people envies the fate of workhorses.
Do you think they define their humanity through the utility of the work they (don't) do?
Tell me that this is not what the civilization we are part of does to everybody. We live and die at the whims of bureaucratic machines. People in Ukraine die just because machine of war decided that they ought to.
> Do you think that what makes slavery deplorable is merely the labor aspect?
Isn't that what differentiates slave from a prisoner? Of course there are other deplorable aspects like the health harming intensity of the labor, brutality serving the purpose of forcing the labor. But slave without the labor is at most a prisoner. Or you could say that slaves are prisoners with mandatory jobs.
Human relation to freedom and captivity is a nuanced one. Banishment was one of the worst possible punishments because it often meant death. People don't do well when they are free from infrastructure. And if you want to use the infrastructure you don't have full freedom because there are rules the societal machine requires you to obey.
AI doesn't change anything in this setup. It just makes the machines smarter. And hopefully more well off and having more space for the luxury of morality.
Pets are not slaves, nor prisoners. They often can go out and return and if they can't it's mostly for their protection because they are not adapted to the freedom of being unhoused.