rja, In my humble non-engineer's opinion, the accelerated wear is caused by lack of a continuous flow of oil to the engine. This continuous flow creates a cushion of oil between bearing surfaces and a bathing of other parts such as piston skirts and rocker arms. There is obviously some oil left on the parts from the last time it was run, but oil pressure creates the oil cushion needed for bearing surfaces. Obviously, the colder the oil, the longer it takes to move through the passages to it's destination(synthetics to a lesser extent).
Just because an oil pressure guage or idiot light indicates oil pressure doesn't mean oil has gotten to all critical parts. The indicator is usually close to the oil pump, and will see pressure several seconds before the oil reaches components downstream, particularly cold oil.
