[ajb]

What he says is " Siri and Alexa and “Hey Google” are already always listening, the conversations just aren’t being saved yet". That's functionally what you describe. Hardware wake-word processing is a power saving feature, not a privacy enhancement. Some devices might not have enough resources to forward or store all the audio, but audio is small and extracting text does not need perfect reproduction, so it's quite likely that many devices could be reprogrammed to do it, albeit at some cost to battery life.