[fuoqi]

"Properly constructed and operated landfills" which prevent leakage of microplastics and toxic decomposition products into air and waterways are far from being cheap, especially on longer time frames and with involved volumes (more than 80M metric tonnes per year just in US!). Usually, you either end up with slack maintenance, resulting in eventual pollution of the environment, or you export this waste into third world countries with significant amount of such "exports" ending in oceans.

And plastic does not stay inert in landfills forever either, it slowly decomposes, releasing products into environment (methane and carbon dioxide being most benign of those). Effectively, you get slower, less controlled and more dangerous (biologically speaking) "burning" which will be done for many generations instead of burning the stuff right away in controlled conditions.

[Retric]

Dumps are the ultimate expression of surface area vs volume.

A single 2200 acre landfill can handle 5 million metric tons per year for ~250 years. 80M metric tons isn’t a particularly big issue from an environmental or cost issue it’s all a question of collection and transportation to disposal sites not long term storage.