If oil out of the ground (crude) were free, gas would still cost too much because of federal and state taxes. plus the expensive government mandates such as gasahol,low sulfur, etc.
Look at the price of fuel oil. In this state it costs as much as diesel because of government regulations and taxes, when it probably should be about half the cost.
https://www.dollartimes.com/inflation/items/price-of-a-gallon-of-gas-in-1968
https://www.tititudorancea.com/z/us_diesel_onhighway_retail_prices_graphs_history.htm
The last two daze of fly-over-country surface travel indicated that:
Diesel wuz YUGELY overpriced vs. gasoline.
Watts-up-wid-dat?
[I left my Diesel carz at home..]
way