I’ve commented before that I expect Google to add more ads, in more areas and places that currently don’t have ads.
The Verge has a great new article out discussing how Google is about to add a lot more ads to their mobile view pages: https://www.theverge.com/2019/5/14/18623541/google-gallery-discovery-mobile-ads-announced . As more of the web is consumed via the phone/tablets, this is going to help Google’s bottom line more and more.