"Google has now stopped providing driver binaries and device trees for Pixel devices as part of the AOSP’s code."

I went and found the tweet. Damn. I remembered it incorrectly. It seems the omission was intentional because they want to support a cheaper reference device, one that's not a $1000 Google device. That makes sense, but damn does it hurt custom ROMs. "AOSP needs a reference target that is flexible, configurable, and affordable — independent of any particular hardware, including those from Google.” That said, in the for decade of custom ROMs, most popular devices form Motorola, HTC, Samsung, etc were all getting the custom ROM treatment and none of these had device binaries or radios released.