The article omits a real, serious source of microphone data though: your smart TV. I know beyond a shadow of a doubt that my TV (a Toshiba Fire TV, although I’m sure many do it) is listening to every conversation I have within earshot, even when I am not using the voice remote, and selling it to ad networks.
And of course it is also doing screen recognition (the kind of stuff OP article mentions), but that is not what I’m talking about. I’m talking about microphone data picking up live conversation from people in the room.