You are absolutely correct that they are not mathematically identical. I struggled to word it in a way that would not mislead people, the distinction is important to emphasize.
In all of these models, the giant variable that is completely ignored is the actual choice to rate something at all, versus skipping over it and reading the next one. That's a very significant decision that the user makes. The behavior of each of these systems w.r.t that effect will be the dominant thing differentiating them.