> Google’s engineers likely gave up on trying to compile custom attention kernels for Apple’s proprietary tensor blocks iirc.

The AI Edge Gallery app on Android (which is the officially recommended way to try out Gemma on phones) uses the GPU (lacks NPU support) even on first party Pixel phones. So it's less of "they didn't want to interface with Apple's proprietary tensor blocks" and more of that they just didn't give a f in general. A truly baffling decision.