The plastic bottles must be shredded and held at optimal humidity/ph/temperature at least. Doubt any bacteria will ever be able to break down so quickly solid material in natural environment. Does not happen with wood and there was quite a longer evolution time available.
This is one of the things that bothers me about how PLA is marketed as biodegradable green plastic. Yes it can break down but the conditions for it are incredibly specific that only a handful of facilities exist to do that in.
It is 99% marketing, and until or unless there is a real economic incentive to actually deliver on that marketing it will continue to be legally possible but practically non-existent.
