I agree that there should be better control in steam over what games are prioritized for both updates and shader caching.
But I was under the impression that most shader precaching was done by compiling locally in the background (via fossilize), not downloading. I agree that a 10GB download for AHIT is sus, but I don't see anywhere on the screen that denotes it is downloading shaders.
Nonetheless, the shader pipeline problems of these new APIs (both pipeline explosion and caching) are not solved yet. IMO caching is not solved because GPU vendors don't allow their new drivers to work with "old" shader pipelines. They have no incentive to (it would require extra driver work, and you couldn't force users to use your latest compiler optimizations), and gamers don't know to ask for it.