Yeah, the point the article makes isn’t that corporations don’t have power, but absent a metric it’s hard to make coherent arguments about how it increases and decreases over time. I would sidestep this by converting a large amount of corporate power into state power by nationalizing large corporations (I mostly think that the state should gain ownership over corporations as part of the bailout process when we determine companies are “too big to fail”) but it also probably is worthwhile to come up with some kind of measure to formalize the influence of corporate persons in the public sphere.