Mining demand is volatile and will use whatever gives them best hashing/$ ratio - pissing miners off might lose you some cash short term but gamers are much more susceptible to branding, and not to mention devs optimise for popular hardware - if AMD suddenly became a major market % holder in the gaming market because NV shipped their silicon to miners, once mining dips down they get slammed. And if they are hoping production will ramp up to match demand some time in the future they still want to have a winning product.