I still wouldn’t believe it. Even the 404 article does not confirm anything and the ad company does not provide any details.
This whole thing feels like marketing, claiming something outrageous to get people talking about your company.
If all your different apps were listening, wouldn’t they be streaming the audio constantly? Wouldn’t they be running speak-to-text constant on the background to extract keywords? Are there any known ways to turn on a mic without app permission or an OS indicator in either iOS or Android?
It really doesn’t seem plausible.
The creepier part is that they can know you so well that they can basically read your mind based on what you do online. Forget bugging you, they just steer you to where you will knowlongly spend the most.