Earlier quoted context omitted.
The cost of landfill is really low, so it wouldn’t make any difference if it were added to the cost of plastic. The world has a lot of important environmental problems, like climate change. Landfill space is not an important environmental problem. You should spend your worrying energy on something else.
A meta study of papers doing lifecycle cost analysis of the options shows that on several metrics, including climate change reduction, landfill is worse than both incineration and recycling for a broad range of materials. This is why almost every functional government in the world legislates accordingly. This is partly due to the energy cost of new vs recycled so somewhat ironically landfill becomes a slightly better…
i very, very much doubt that said study existed at the time these decisions were made.
also the energy cost is a wash (or loss) for almost all but aluminum. glass would be fine but we are awash in glass, so AIUI cardboard and aluminum are the only consumer items worth recycling when consider energy and other input costs. i’ve no idea on total climate impact (eg greenhouse gas production) though and i don’t doubt you. i only doubt your assertion that governments made these decisions with that in mind.