Most websites are funded with advertisements. Income is needed to feed the author etc. For many years some sites used paid for click ads. These are no longer widely used. We have used Amazon for a long time who are a commissioned ad. We only earn if somebody actually buys. CPM ads have slowly recovered but valuations are far lower that they were mainly as there far more websites than ever..
CPM ads have had had their own share of problems. Valuations have fallen considerably since the .COM bubble era.
This site which uses WordPress has a sidebar which lends itself to a conventional display ad. This design favors CPM type ads which is the traditional method of earrings. CPM ads generally do not attach any value to clicks but some may pay a commission for a sale.
Ad blocking has risen mostly due to problems that are very complex to analyse. Some sites have 99% ads with 2 lines of text.
Thi site is content driven like the majority of sites. It’s the bad apples that cause problems. We divert blocker users away from the site landing page.