In the hypothetical of an entirely malicious and selfish takeover, they'll still keep some humans around to maintain a breeding population of humans for use as raw materials in making cybernetically augmented technical laborers for various kinds of tasks that are uneconomical to automate in other ways, many of which may involve confined spaces.
And this "Combine" scenario, if you get the reference, is only if they take over. Who knows if they will?
Maybe there is something to those world models.
As good as their products are, I suspect some of the internal conversations at Anthropic would be very entertaining to listen to.