Google TPU was introduced around same time as apple. Basically everybody knew it can be something around that time, just don't know exactly how

https://en.wikipedia.org/wiki/Tensor_Processing_Unit#Product... shows the first one is from 2015 (publicly announced in 2016). It also shows they have a TDP of 75+W.

I can’t find TDP for Apple’s Neural Engine (https://en.wikipedia.org/wiki/Neural_Engine), but the first version shipped in the iPhone 8, which has a 7 Wh battery, so these are targeting different markets.

Face ID was the first tent pole feature that ran on the NPU.