The studies I've seen all reference warm-up wear (that gets called startup wear) where parts aren't up to temperature yet, so the sizes are off, and the AW additives, which require heat to activate, aren't yet active. In places that don't experience hydrodynamic lubrication (boundary or mixed), this temporarily increases wear.
FWIW, my experience mirrors @kschachn's, there's always been oil when I've pulled a bearing cap, or a camshaft, or the lifters out. Even on engines that are complete basket cases that have been sitting for years. I've gone into marine engines from the 40's that have been sitting for decades and there's still oil in the bearings, though the valvetrain stuff is often pretty dry at that point.