As recently as ten years ago, conventional motor oil consisted of what amounted to Group I solvent de-waxed base oils and shear and oxidation-prone VII polymers. The rest of the additive package was reasonably formulated. Current energy efficient motor oils are at least Group II, with many adding Group II+ or Group III to the mix and much more shear and oxidation-resistant VII polymers. Per automaker concerns, SM rated motor oils have dropped the ZDDP content (and there'll be another drop in the upcoming SN designation in a couple of years), but molybdenum is an increasingly popular makeup compound, though there are other compounds equally or more effective - usually more expensive. There was never anything remotely superior or unique about ZDDP other than it was both effective and C-H-E-A-P. The above poster's cynicism aside, current conventional oils are considerably improved over what was previously offered. Personally, I'd go so far as to prognosticate that SM motor oils were just what sludge-prone Toyota motors needed from ~1996 - 2002.