> Kindles have been showing ads on their lock screen for the ad-supported tier for a very long time now.

Wow, this is wild. I've also remembered that Viber puts ads among your chats in a chats list. It shocked me first time I've seen that.

> patenting

As I understand, big companies are making lots of patents, and most of those never come to life.

If I remember correctly, it was Roku, which is already doing things like this:

https://www.wired.com/story/roku-tests-showing-video-ads-bef...