I think your mistaking the philosophical basis of parents comments. Maybe a more succinct way to illustrate what I believe was their point is to say: "no matter how complex and productive the AI, it is still operating as a form of capital, not as a capitalist." Absent being tethered to a desire (for instance, via an owner), an AI has no function to optimize, and therefore, the most optimal cost is simply shutting off.

A transaction is an exchange between two parties of something they judge to be of equivalent value (and mostly, in ratio to a common medium of exchange).

You can program AI with "market values" that arise from people; but absent that, how do these values arise naturally? Ie., why is it that I value anything at all, in order to exchange it?

Well if I live forever, can labour forever, and so on -- then the value to me of anything is if not always zero, almost always zero. I dont need anything from you: I can make everything myself. I dont need to exchange.

We engage in exchange because we are primarily time limited. We do not have the time, quite literally, to do for ourselves everything we need. We, today, cannot farm (etc.) on our own behalf.

Now there are a few caveats, and so on to add; and there's an argument to say that we are limited in other ways that can give rise to the need to exchange.

But why things have an exchange value at all -- why there are economic transactions -- that is mostly due to the need to exchange time with each other because we dont have enough of it.

Granting your premise, i'd be forced to argue that economic value (as such) doesn't arise from their activity either -- which i think is a reasonable position.

Ie., The reason a cookie is 1 USD is never because some "merely legal entity" had a fictional (/merely legal) desire for cookies for some reason.

Instead, from this pov, it's that the workers each have their desire for something; the customers; the owners; and so on. That it all bottoms out in people doing things for other people -- that legal fictions are just dispensble ways of talking about arragnemnts of people.

Incidentally, I think this is an open question. Maybe groups of people have unique desires, unique kinds of lives, a unique time limitation etc. that means a group of people really can give rise to different kinds of economic transactions and different economic values.

Consider a state: it issues debt. But why does that have value? Because we expect the population of a state to be stable or grow, and so this debt, in the future has people who can honour it. Their time is being promised today. Could a state issue debt if this wasnt true? I dont think so. I think in the end, some people have to be around to exchange their time for this debt; if none are, or none want to, the debt has no value

They are composed of people, though.

Depending on how you feel about various theories of development, an argument that all of these categories reduce to time. At the very least, the relationship between labor, capital, and time seems pretty fundamental: labor cannot be instantaneous, capital grows over time, etc.