That requirement is a bit outdated. At native (not higher than a real gamecube) resolution, I find that the vast majority of games play just fine on Intel HD 40

That requirement is a bit outdated. At native (not higher than a real gamecube) resolution, I find that the vast majority of games play just fine on Intel HD 4000 integrated graphics, and I imagine newer chipsets perform even better. When Dolphin was first released though, Intel graphics were pretty much garbage, so the discrete graphics requirement made sense.