You try producing oil for that price today. The easy-to-get oil is running out. The cost of the deep shale wells with multi-stage fracking and mile or two long laterals are not cheap.
If the cost to produce was like you suggest, the profit margins from the oil companies would be more than a magnitude higher.
So prices went up that much in 15 years due to costs of production? Right.. And they’ve fluctuated as your graph shows from just that as well?