But, this isn't a golf ball - or something with a lot of texture that's gonna generate much turbulence (like a road biker or a human swimmer).

The flow will probably be relatively laminar, right? The leading edge (tip) might cause a little turbulence, but after that, we're looking at a fairly laminar flow until it the molecules hit the fletchings, and are disrupted. This is a flying column with an aerodynamic tip, not something that is going to disrupt the airflow and create turbulence around the shaft.

The real turbulence doesn't occur until the flow of air reaches the fletchings.

I'd argue that the airpassing over an arrow in flight is moresimilar toair moving through a straight pipe than it is akin to a turbulent disturbance around the leading edge ofa flying golfball.

Also: People are willing to pay $12 a high-end carbon arrow right now (without adding the price of a head). They would pay more if the added benefit met the price. Besides, I don't think it would cost $25 an arrow to coat them. They sell teflon-coated generic pans at the Dollar Tree. It can't be that expensive - especially under an economy of scale.