That strikes me as a forced correlation. Something along the lines of "some people are willing to pay more for British racing green, so let's charge $X for it".

I really don't think that's a big factor in this, at least in modern times. Maybe it was once the case where colour was difficult or something.

I mean I see the inverse as true, and entry level vehicles seem to have the most colour diversity in their sales. It is cars like the Nissan Versa where you see real colour variations.