> purpose of work is to serve humans

I don’t think that you and I are going to disagree on that.

This is not an argument about philosophical values. This is an argument about incentives and reality.

> humanity is free to do whatever we like while the machines keep up well-supplied

The problem is that the future tends to arrive in an inequal manner. Some group of humans will have more control over the machines which keeps them well-supplied than others. Let’s call these humans rich&powerfull. The rich&powerfull one day going to realise that the machines are keeping them safe, well-fed, and entertained. They might at that point ask why they suffer all the other people gumming up the works around them. They might not immediately order their robots to murder everyone who is not them, but simple plain indifference can do wonders. Maybe they would ask the robots to move along those closest to them. (In the name of security and privacy naturally!) Or maybe they ask the robots to remove those who disturb their views by living in areas visible from the rich&powerfull’s homes. And then imagine what happens when the common rabble get together and does a “democracy” where they try to limit what the rich&powerfull can do. If this so called “democracy” doesn’t own a robot army, or said robot army is leased from the rich&powerfull they might find that they can’t enforce those laws. If the common rabble gets upity and tries to hurt the rich&powerfull with pitchforks that is just further reason to arm more robots and surpress the common folk more. After all one can never be carefull enough. The rich&powerfull might ask themselves why they are spending resources on making robots which feed the common folk, or protect them, or heal them. They don’t turn off those services altogether. They are not monsters! Just neglecting them more and more. After all it does not make their life harder, so why not?

It is not like anyone made a decision that humans are not worth feeding. It is that the rich&powerfull decided whatever strokes their fancy is worth the resources more than feeding the not rich&powerfull.

It doesn’t necessarily means that these rich folks will live surrounded by only robots. They might have a bunch of real human girl/boyfriends, and hanger-ons, and court poets, and whoever they fancy. But these “courts” can be drastically smaller than our current societiess, and much more idiosyncratic.

Now of course you might say this is a bad sci-fy plot And you might be right. There are a few assumptions under it.

One is that it is possible to make machines which can perform all these jobs (manufacturing, agriculture, transport, and security to name the few main ones). We can’t do that as of now. We think we will be able to do all of these with machines one day but we might be wrong. If we are wrong this scenairo won’t ever come.

The other assumption is that control over these machines will be easy to centralise. This future won’t come if everyone can grow a robot army in their own kitchen for example. But i think it is more likely that at least initially these technologies will require expensive factories, and expensive IP to be produced. And those tend to be concentrated in a few hands.

Who knows maybe there are other assumptions too. Have to think more about that.