How do you expect people to discuss them across the scale of a whole economy without giant spreadsheets? Externalities are a well understood economic concept whose study goes back a century.
The economic concept implies that we're going to have an evidence-based discussion about how we're tracking specific dollar cost amounts of pollution or something, and then in practice that essentially never happens and it's just "I've decided you don't really need that thing you want"
How do you see it differently?