Which is why open source is important. Holes can be found and software telemetry can be avoided.

A lot of the telemetry is sold to people as being in their benefit. Monitor installed software for updates, location data for weather etc.

If the companies had to document the amount they collected in cash for each user based on ads and send it as a mk though report, it might be eye opening. The source if the cash would also be good. So did companies pay directly or dodgy intermediaries and data brokers.