No, it's because most of the "blackest" finishes are extremely delicate, as they rely on a sort of micro-velvet structure to trap light as well as absorbing light. There are relatively sturdy solutions - fabrics, mostly - but they tend to be absolute dust magnets, and look rather ratty in a short time unless kept scrupulously clean. Between the high maintenance and the immediate grunge regardless of maintenance, they don't sell well. (Photographers, on the other hand, love the stuff despite the fact that there's an extra few minutes doing a detailed tidying before every shot.)

Polarized sunglasses will significantly reduce the visibility of dashboard reflections.