That’s susceptible to all kinds of excuse making and allegations of sabotage and cruelty and messy edge cases and would be extremely difficult to pull off in a way that satisfies zealots, but it’d have the massive benefit of actually comparing systems outside of any given framework for reasonable people.
My own personal theory is that any given economic system’s benefit is related to the collective psychology of the populace and that there are different local maximums and systems that work better in certain situations than in others.