Petroleum-based oils incorporate molecules of hydrocarbons as well as additives such as paraffin, salts, and metals as seen here https://emotiionssad.blogspot.com/2021/04/processed-petroleum-oils-mail-valves.html .Each of these molecules have slightly different reactions to heat, moisture and oxygen, so it takes a lot of fiddling around with each hydrocarbon to get them all to work in unison throughout a wide range of temperatures and over an extended period of use.