Apart from the other points people have made, it's worth noting that these days parents can avoid having children with inherited genetic disorders through IVF.

Apart from the other points people have made, it's worth noting that these days parents can avoid having children with inherited genetic disorders through IVF. While there will always be a component of spontaneous mutations resulting in genetic disease, we may approach within a couple of generations a state where most inherited disorders actually disappear or reduce to vastly lower prevalence over time.