That's probably exactly it - ATI has usually used Sapphire to make their reference cards and ATI-manufactured cards. Many vendors make specific changes to the bios, use out-of-spec or pre-overclocked parts, etc.

To put this situation in better perspective: If Intel made bioses in addition to their current products, and they released a bios update for their motherboards (with Intel bios and Intel parts). Here, he's mad because he has an Asus motherboard with an Intel bios, and since Asus isn't releasing this bios update, he won't benefit.