What this demonstrates is how good tracking is now. They’re not listening to your microphone, at least not while your phone is in your pocket or whatever, because they don’t need to. They can already see your fingerprint, what websites you’re visiting, what your searching, and all of this applies to people you know as well- people who likely aren’t privacy conscious and share all contact info with whatever app is requesting. Listening to the mic is not necessary to suggest highly relevant ads.
How many times a day are you shown ads that are completely irrelevant?
Me personally, I’ve never once experienced the “they’re listening to my mic for ads” phenomenon. I think someone would notice by now either by seeing increased upload usage or a hot device- at least with current technology. On device machine learning will make this much easier to analyze without having to upload audio.
Not that I don’t think it’s entirely possible to listen right now, I just don’t think it’s occurring to unimportant people. I’m not particularly important or rich nor is anyone I know. It seems much more plausible to me that we’re just seeing conventional web tracking get a lot better + a healthy dose of confirmation bias.