I don't think substitution to synthetics is very common for the reasons you mention. Oil substitutes such as ethanol have been driven by government policy not e

I don't think substitution to synthetics is very common for the reasons you mention. Oil substitutes such as ethanol have been driven by government policy not economics and would mostly disappear without subsidies. True synthetic oil products are very rare. Instead persistent high oil prices and new technology have made previously uneconomic oil sources economically viable.