Both. Pollution externalities are basically unpriced, and oil production is massively subsidised. Governments suffer from hyperbolic discounting - they would rather keep gas prices low for the next election than deal with the expensive and difficult long-term process of transitioning to more sustainable sources of energy.
"also all economic actors discount the future at varying rates"
Which future are you referring to, the near future? Economic actors generally care about the profit which is closest to them, any consideration of the future beyond that is considerably weaker.
Also, consideration of economic actors is an abstract idea, what is being discussed is the reality of what exists today. What would you propose for ensuring the overall costs were more completely reflected in the final price?
