(nods) Got it.

On your view, is there any attempt at internal coherence?

For example, given an X such that X is equally practical (economically) in an Athenian and post-Athenian economy, and where both Athenians and moderns would agree that X is more "consistent with" slavery than non-slavery, would you expect Athenians to endorse X and moderns to reject it, or would you expect other (non-economic) factors, perhaps random noise, to predominate? (Or some third option?)

Or is such an X incoherent in the first place?