Any oil that doesn't mention PAO's/Esters is most likely a Group III oil. All are GIII, unless the say otherwise on the bottle or website, is an easy way to look at it.
Nothing wrong with GroupIII. But, seems that there are 'good' and 'bad' group III base oils. This is why we have some automaker specific GIII motor oils and ATFs. The groupIII basestocks from various suppliers are not interchangeable. PAOs/PIOs.... have that interchangeability.
I was under the impression that EOPs blends are used by Pennzoil in their synthetics. SOPUS also has some fancy XHVI basestocks too.
We also see that some GroupIII oils have been reformulated over the years to meet more demanding better spec's. So, some have a shot of group IV/V in their formulas now for better cold flow/pumpability, and less oxidation/sludge at higher temps.
I definitely understand the 'true winters', the sludge monsters, the turbo toasters, the undersized sumps, the rpm junkies, the lugging shortshifting crowd........ and why I would pay more for a real IV or V synth oil.
My vehicles are not disposable. Marketing/advertising, which gave us group-III, also gave us maintenance free disposable cars which the consumer loves to lease or trade in all the time.