It was already known before the whistleblower that:

1. Siri inputs (all STT at that time, really) were processed off device
2. Siri had false activations

The “sinister” thing that we learned was that Apple was reviewing those activations to see if they were false, with the stated intent (as confirmed by the whistleblower) of using them to reduce false activations.

There are also black box methods to verify that data isn’t being sent and that particular hardware (like the microphone) isn’t being used, and there are people who look for vulnerabilities as a hobby. If the microphones on the most/second most popular phone brand (iPhone, Samsung) were secretly recording all the time, evidence of that would be easy to find and would be a huge scoop - why haven’t we heard about it yet?

Snowden and Wikileaks dumped a huge amount of info about governments spying, but nothing in there involved always on microphones in our cell phones.

To be fair, an individual phone is a single compromise away from actually listening to you, so it still makes sense to avoid having sensitive conversations within earshot of a wirelessly connected microphone. But generally that’s not the concern most people should have.

Advertising tracking is much more sinister and complicated and harder to wrap your head around than “my phone is listening to me” and as a result makes for a much less glamorous story, but there are dozens, if not hundreds or thousands, of stories out there about how invasive advertising companies’ methods are, about how they know too much, etc.. Think about what LLMs do with text. The level of prediction that they can do. That’s what ML algorithms can do with your behavior.

If you’re misattributing what advertisers know about you to the phone listening and reporting back, then you’re not paying attention to what they’re actually doing.

So yes - be vigilant. Just be vigilant about the right thing.