(author here)

Thanks for this comment. I am remiss to not directly address how this ties into Marxist theory. I'll consider how to add references on the next rewrite.

A key point in Mag Wealth is that there are several meaningfully different levels of both labor and capital. "Capital" is generally regarded as $^6 and up, whereas "labor" is below $^6. But just as there's a huge difference in the lives of a waitress vs lawyer (though both are "labor"), there's also a huge difference in the lives of a millionaire vs a billionaire (though both are capital). There are people who are unable to work and have even less opportunity than a minimum-wage worker; are they "labor", or maybe we should call them something else, like "destitute"? And there are people who have hundreds of billions of dollars who buy and control institutions of power; are they "capital" or do they become effectively "sovereign"?

I would still refer to them as capital. They might have more money than the gdp of a small state but that doesn't mean they are a state.