I thought this was obvious. It's not. I have a better summary than the link.

We're entering a paradigm shift in what "investment" means. It used to mean that for a given amount of cash, you might get returns in the realm of many multiples of the initial investment (if the risk pays off).

But at some point in an economy like ours, there is no more investment to chase. Even if you could make an investment that would bring in octillions of dollars (whatever that means) what would be the point? What could the investors hope to invest those octillions in? What could they buy with it?

Well, one of the things you can buy with it: a world of high tech luxury that you don't have to share with 8 billion other people. Those people will cease to exist (sooner or later) if they are cut off from the economy. You'd have to of course manage them in the meantime (they won't cease to exist instantly, and might cause trouble if they become aware of their pending fate), but they'll just be gone. For your high tech luxury you would need some sort of system to build and maintain the high tech luxury, a system without those humans that you intend to eliminate (even if you plan to just let them wither away)... something to build your megayachts and prepare meals and harvest the truffles and raise the sturgeons. That system certainly requires some sort of artificial intelligence.

We're heading down that path. I won't call it a conspiracy, it probably isn't one. It's just the path of least resistance.

There is almost certainly some sophisticated theory of economics that incorporates these potentialities. It would be the general relativity to orthodox economics' Newtonian. But, there would have to be economists left after all this goes down to even come up with that sophisticated theory, and those who remain won't be interested enough in the science to study economics. It turns out that humanity is fungible too.