There obviously is reputation and legal consequences. You can get fined for billions for a far more indirect privacy violation that what you are describing. If any big company ever does that, I won't be touching it with a 10 foot pole. And no I don't believe using data for showing me ad is on the same level of privacy violation.

[1]: https://www.ftc.gov/news-events/news/press-releases/2019/07/...