Unless laws exist to prevent this, you can bet that ALL BigTech are doing this, to varying levels. If they are not doing it in your country, you can bet they are doing it in other countries. The US government incentivised them to do this with the PRISM program ( https://en.wikipedia.org/wiki/PRISM ) and showed them the value of collecting user data even if they do not need it (right now) for their services and products.

That services like Alexa, Siri, Cortana, Assistant etc. exist with 24x7 listening devices shows that cost is no longer a hurdle in deploying this at scale. And note that they do not have to upload the audio files (which by the way, they can - I remember Google showcasing an audio codec - https://github.com/google/lyra - that is suitable for very low bandwidth, so neither bandwidth nor storage is a big issue today). Today's phones also have enough power to transcribe the audio on device itself (e.g. Google Live Transcribe feature now works when offline - https://9to5google.com/2022/03/10/google-live-transcribe-fea... ). Why do you think there is a sudden push now to put AI on SoCs and thus on device? It's partly because BigTech want to offload more and more processing on to your device. We are at a stage where hardware has outpaced system software development and is actually underutilised.

(And we are also at the techno-cultural cusp where the ownership of most of our devices are questionable, and moving towards a dystopian future where we will no longer be able to claim rights on these computing devices).