What are the possible explanations for that? 1) Peak oil plateau - within the areas available to the IOC's, the geology simply will not support higher extraction rates. 2) Over-regulation - they are not being allowed to drill in places that could support higher extraction rates. 3) Under-investment - the IOC's have failed to invest in exploration, development, extraction, and extended recovery techniques that would support higher rates. 4) Short term greed - they are more interested in profits today than in increasing extraction rates. (corollary - they don't think they can increase extraction rates so they might as well minimize costs and maximize profits).