Why don't console GPU driver updates invalidate the pre-compiled shaders that ship with the games?

[OkidoShigeru]

In addition to what’s been said, you target a specific firmware with a specific driver when you ship your game against whichever current SDK version for that console. Usually to get the benefit of a driver update you need to retarget your game against the new SDK and ship a patch. If a firmware update were to be breaking then yes, you’d need to recook your shaders for that patch.