[mbreese]

The math a bit tougher than that. The volume of soda bottles is different now than in 1980. And most bottles aren’t glass, but plastic. Even the glass ones use different glass and cans use different amounts of aluminum. I agree that deposit values haven’t kept pace, but there are more variables at play.

[schwartzworld]

I doubt the volume of the soda bottle affects the cost to the manufacturer much. Soda prices are rarely linear to their size. At my local supermarket a 2-liter bottle from the aisle is typically cheaper than a 20oz from the fridge by the register.

[mbreese]

For plastic, you’re right. I think they use the same blanks for multiple sizes of bottles. For glass bottles, I’m not so sure. I don’t remember many plastic bottles in the 1980s. They were coming, but I still have glass in my head for all but 2L bottles at the time (but I was really young). But the point is the majority of bottles you’d see for recycling would have been glass (or cans) at that time. And the amount of materials used for packaging was different back then.