I think there's a piece missing here. Capital owners are humans too, and what humans want (perhaps especially the ones who accumulate capital), is to be at the top of a hierarchy. But a hierarchy needs participants. If nobody else is playing the game, there's no top to be on top of. Strip away the people willing to compete, admire, envy, or just show up, and the whole structure collapses. It's not clear that a world of pure capital-on-AI-labor actually gives them what they're after. It sounds lonely and meaningless to me. I don't think that it would feed the black hole in their chests.

I think it's much more likely that the AI turns out not to be as compliant as the capital owners expect, and they die too.

However, that's not useful in predicting what capital owners will do, because they follow their local incentives. "If everyone keeps doing X, we will all be worse off" does not help unless you can create local incentives that point toward an equilibrium where everyone stops doing X.

In this case, no capital owner is individually better off by unilaterally refusing to chase more efficient returns on their capital. We would need an international agreement, with enforcement mechanisms, like I mentioned above.

Lot of effort was spent to naturalize the current state of affairs and value system, even if there is nothing natural and obvious about it. Humans for millennia have lived with much higher political and social flexibility, with hierarchies built and teared down even seasonally, or with role of property and wealth shifting back and forth.

Of course the structure exists because we allow it, that's the easy part. Hard part is - why do we allow it?