All oils are 'dinosaur oils' or whatever you want to call them. The difference is in the refining process, and additives.
Synthetic will last longer and tend to not burn up as much because the hydrocarbon chains are all more consistent (closer to the same length, therefore viscosity, and ignition characteristics). Cheap oil has lots of variation in the hydrocarbon chains and the shorter ones are more volatile and burn up faster... hence 'coking' / filth, whatever you want to call it.
If you need zinc, or whatever, then buy the oil that has what you need.