It still biodegrades within the pit. In fact, that's actually a problem because it can generate fire starting temperatures! (Crazy I know) It's also a problem because a part of biodegrading is producing CO2 and CH4.

But I generally agree. The big issue here is we as a society have moved away from biodegradable packing and distribution. I get it, plastic prevents waste and mold. That's why we use it. It's also dirt cheap. It's a byproduct of oil refining (literally cheaper than water).

The ultimate solution to the plastic problem is making plastic more expensive, and the way to tackle that is by reducing oil consumption. Fortunately, that's sort of just naturally happening.