"In fact, oil cost about 50% more per barrel in 1979-80 than now when adjusted for inflation."
This is a completely bogus statement.
That fact is the more you make of something, the cheaper it should be for the unit price based on the nature of mass production yet, this is not occuring. The problem is that we are making more and charging more if not in the taxes but the burdens and, the profit demands made on the company by stockholders.
Sure it is.
You're making one rather glaring omission:
At the same time production of petroleum has increased, consumption has increased enormously due to the rising purchasing power of India, China, and others.
There's another economic principle having to do with supply vs demand at work here.
Unless, of course, the demand for the 'something' is increasing faster than the supply. In which case, the price should rise. Which is exactly what has happened.