Which is why it pains me so much that my municipality doesn't include (at least a household food scrap sized) compost bin with standard garbage service. They only offer a giant and expensive yard-waste bin.

That's why I mentioned long term, as you expand the time horizon you consider it over, landfill for plastics gets worse as it starts to decompose compared with incinerating with energy recovery or recycling.

Define long-term? I think that, as you expand the time horizon, you'll first reach the point at which the landfill gets buried, effectively sequestering the plastics and the carbon within.