Here's a chart from a motored engine test (not fire, no heat of compression) on a 1.5L 4 cylinder. You can see in the left of the curves the operation in boundary lubrication (which you don't believe in), moving to the predominance of hydrodynamic to the right.
As you well know, power is torque times revs per second (times 2Xpi).
So taking the blue line (ILSAC 5W30), the frictional power losses that go into creating heat in the oil (and coolant, as main bearings flow heat INTO the coolant at high revs) are 1.2KW at 1,600RPM, and a massive 4.2KW at 3,200RPM.
Science matches my observation surprisingly.
Then look at the blue line at 3,200RPM, versus the dashed red line, with is a 20 grade, high VI, with advanced friction modifiers...it's frictional losses are 3.6KW...less frcitional losses means better economy, and a slightly longer warmup.
All this BEFORE you even light a fire over the top of it...and it all exists at RPM, regardless of actual engine load.