I'm in no position to argue one way or the other about whether the abiotic theory is right or wrong and to what extent, but from what I've seen so far, in comments, I would say you need to read the literature. (1) The US and Europe, and probably most other oil producing countries, do not subscribe to the abiotic origin theory and therefore are not looking in the right places (the proponents maintain). So, it's no wonder their output is declining, if you accept the deep origin idea. (2) The other question posed is who stands to gain from maintaining an obsolete theory of oil formation and constant oil shortages?  Answer: The same groups who are not looking for abiotic Oil.  Mageru's comment about the speed of production of new oil or the commercial viability of abiotic oil are legitimate criticisms that have been raised, and good answers can only be realized with research and time.

The downside of unlimited oil would be an unbearable continuation of trends as we see them now. More cars, more pollution, more urban sprawl, global warming, etc, etc.  

 

I can swear there ain't no heaven but I pray there ain't no hell. _ Blood Sweat & Tears