I don't know if the author is on HN (also not sure what difference this makes) but a payout of $100k made the news recently for https://bhavukjain.com/blog/2020/05/30/zeroday-signin-with-a...

A few days later another researcher reported earning $75k for webcam access vulnerabilities: https://www.ryanpickren.com/webcam-hacking

These payments are not uncommon.

Yes it does happen: https://gizmodo.com/apple-pays-developer-100-000-for-finding...