True but the oil never left. And even if the oil film thickness decreases it will happen faster with warm oil.
I’ve disassembled junkyard engines that were at least a decade old and oil is still covering all the surfaces.
After a decade, did they incur a higher wear rate on the cold restart than during the rest of their lifecycle? Drained restarts are necessary, but are they not also less than desirable?
I never understand the logic. How does one get a cold engine? By letting a warm engine cool down. If the oil evacuates more when it's warm, it's not like it goes back there after cooling. You don't get to credit the cold state if it got there by cooling, parked, from a hot/warm state. Four possible scenarios and infinite intermediate variations:
1) Hot running engine. Park and immediately dump.
2) Hot running engine. Park until cold. Dump.
3) Cold running engine. Park and immediately dump.
4) Cold running engine. Park, wait, and dump.
So was the last "well lubricated" state hot, or cold? If there's any time a motor has the most chance/quantity of retained oil "sticking to" parts, it would be if it's been cold cranked and run for a short time, but not enough to get to temperature.
There is no way the period of startup idling with an empty oil system is good for the engine, or that the air getting pumped out of the system doesn't push oil off some important journal somewhere. How long is it okay to idle an engine without oil pressure before longevity of the motor is impacted in some way?
I get it. Film strength, adhesion, and viscosity are not one in the same, but there has to be some relationship.
EDIT: I guess my concern is irrelevant to the thread. I'm mostly concerned about the empty galleys that result from a filter change. (I am less concerned about the half quart of serviceable but dirty oil that is left behind.) The OP was about oil changes and didn't explicitly specify an accompanying filter change.