Do compostables break down faster in a landfill versus other items?
Microorganisms, carbon, water, and oxygen are all necessary elements of composting.
If compostable products are sent to an open landfill or dump where oxygen is available, most will degrade at a rate similar to other biodegradable materials in the same setting.
If compostable products are sent to the more common air-tight landfill and deprived of oxygen and microorganisms, they will decompose over a very long period of time along with all other waste brought to these facilities. These kinds of landfills are not designed to break down waste, only to store it.
Despite this fact, there are significant upstream benefits of compostable packaging including being made from renewable, less toxic materials by conscientious companies. For more information, check out this article about this topic.