Is it really friction, though? It seems to more like a case of one layer inducing mechanical work in the other, which in turn results in loss of efficiency due to inertia and actual friction within the layer.

In other word, I read this akin to an inductive coil moving through a magnetic field and drives a motor with a load. This will cause the coil to resist the movement, but it can hardly be called friction.

It seems more like a case of one layer inducing mechanical work in the other, which in turn results in loss of efficiency due to inertia and actual friction within that layer.

Now, define friction.

I know that sounds like just a pithy response without much thought put to it. But actually, that may be what friction is. I’ll also note that nothing about physics and the interactions of matter is actually as intuitive as it appears. For example one might say, “well friction is when two materials touch and rub against each other” but remember, materials never actually touch, the molecules of each material are only ever near each other at best. So what is happening that causes that resistive force?