So you are saying that apps on your phone can access your microphone without your permission? Wouldn't you want to report that to Google or Apple or whoever made your phone's OS?
Also, how did your individual phone become relevant for the assumption that this is a widespread phenomenon?
Finally, it's great that you log your app activity, but you are aware that the scientist in the study I cited examined 17620 apps and found not a single instance of the app turning on audio and sending the data?
I happen to work in machine learning. You are most likely referring to the Stanford Gyrophone paper. Given that the sampling frequency of the gyroscope sensor on typical smartphones is extremely limited, you can only get very low frequency content (Nyquist).
It wouldn't be possible for any human to process or understand the recorded signals, so the researchers trained a machine learning model on the recorded samples, with a very limited vocabulary consisting of only the digits from 0 to 9 and "oh".
If the model was not trained on the particular speaker (requiring annotated training data for that particular speaker, which would be almost impossible to get in the assumed scenario), the recognition rate was 26%. For a vocabulary of 11 words.
It's a nice proof of concept, and doubly so if tge CIA considers you a target, but otherwise it's not happening.