Plastics and other oil-derivative, crucial materials should be the main use of crude oil and methane, not energy. Save the oil to make things that don't have an easy replacement. Replace oil burning with solar, wind, nuclear, etc., and use the underground reserve of hydrocarbons for noble causes like medecine, or for the type of investments that add to the net good for our species.
Plastics can be made from pretty much any plant-derived oil. Heat some vegetable oil, and voila, you have essentially plastic gunk and toxic side-products. The root problem is we have corrupt governments around the world in the pockets of big oil who don't care about the survival of the species or the planet long term so long as they advance short-term profits and expanding demand for oil.
