Since it takes millions of years for organic matter to turn into oil, I'd say offhand that we're over using it.
There was an attempt to speed up mother nature by making oil from turkey guts, but the plant went out of business.
Not because the process didn't work but because the EROEI wasn't sufficient.
And actually, they tried a wide variety of recipes, from turkey guts to broken up pieces of plastic computer monitor cases.
The anaerobic depolymerization process employed by Changing World Technologies was trumpeted as the newest in a long line of
ideas centered around anaerobic thermal depolymerization, but both the vagaries and limitations of Newton's laws on thermodynamics
kept raining on their parade because optimistic projections failed to account for piddling details like cost of raw stock transportation and the energy
required to chomp all that plastic and meat renderings into sufficiently small pieces.
In the end, when considering any trash to fuel or trash to energy scheme you can't lose sight of the fact that you're dealing with trash
and trash takes up space, and trash weighs something but the energy content of trash is either locked up in molecular bonds which
are difficult to break or there isn't enough to make it worth dealing with...which is why it's trash.
The turkey guts were easier to get because CWT was close by a turkey rendering plant.
The plastics were the sticking point.
Now, if your main goal is to simply get rid of trash, you locate next to a dump, and you also get the extra energy input from methane in the dump, which can possibly help power your depoly process. Vernon and Commerce, California have had a trash to energy plant for twenty five years but their main goal is to reduce landfill use. The energy output is just a bonus but not really a net energy plus.
It powers about 20 thousand homes but repeatedly runs into emissions issues.