I find it hard to believe the parent was failing to account for the cost of the landfill. It's the most obvious cost of that strategy, so it would be hard to miss.

On a related topic, to know that the equilibrium changes, you'd need to know the difference in cost before and after accounting for the thing you added.

This discussion would benefit significantly from careful analysis using actual numbers. If there's one thing that Bullshit! got right, it's that there are clear, empirical metrics we can use to evaluate solutions, and we should use them.