The misconception is that oils lube because they're "slippery".
Actually, they lube by hydraulically separating parts from each other.
To this end thinner oils will do this quicker and more easily
than thicker oils.
As far as thicker oils clinging to parts at rest, drop a camshaft
into a bucket of 50 weight oil and it will sink to the bottom,
in contact with the bucket. There is little to no protection at rest
other than from corrosion.
While I do not totally disagree with you I also doubt anyone would want to crank up an engine that had zero lube on anything.
This is also the time an engine gets hammered with wear.
Oil does provide some very important lubrication on start up before proper flow (which I agree provides far more lubrication) is established.
The real question seems to be, what oil type/viscosity provides the best in both situations.
In a related story, A friend used to own "The Buggy Barn" and specialized in air cooled VW service and custom work.
He worked late into the night to build and install a custom 1776 cc engine using lots of a 50/50 mix of STP and Castrol 20w50 as assembly lube. He left the final plumbing and wiring for one of his employees to do in the morning.
The kids goes to work in the morning, gets everything all connected, fires it up and of course romps it out of the parking lot and down the street to "break it in."
Engine starts running like crap so he heads back and after about 8 miles it seizes up. He had not put ANY oil in the crankcase and of course it was trashed.
Without any thick oil film in that engine who thinks it would have driven anywhere near that far?
Built many VW motors and always used my friends homebrew assembly lube.