It’s also kept intentionally scarce by the companies. Why flood the market with cheap gas when you have an oligopoly going on quite nicely. There was just too damn much consolidation in the oil market during the 90s.
Now you understand, It has been a long time since there was a “level playing field” in the heavy industry component of business operations in that territory once known as “the United States of America”.
It is not just the petroleum industry, there is a great deal of “crony capitalism”, the government-controlled form of what used to be capitalistic economic theory, with preselected winners and losers.