"you could chalk some of this up to media strategy focused on search; sites that have been running for years have strong archives and good reputations that cause them to rank high in Google search results. Someone looking for a movie review will see, say, The A.V. Club pop up high in their Google results and click to the page. That’s as far as the Spanfellers of the world care to think; it doesn’t matter if the review is written by AI or illegibly slathered with ads because the company got its click, which translates into the ad revenue or visitor traffic that looks nice in the spreadsheets that are the only way these media owners actually engage with their own sites."
The issue is that ads these days are largely less about actually informing people about a product and more about a well-known brand keeping its market dominance. At this point, there's basically no one who doesn't know about McDonald's or Coke but they still advertise heavily because they want to constantly be on people's minds. They're not really concerned about a return on their advertising investment as long as they're still maintaining their position.
No, just that sales is probably not the only metric they're looking at when buying ads. It's about maintaining their brand image too.
We saw this with Amazon when a bunch of news articles about their union busting and poor work conditions were breaking. There were tons of ads from Amazon about how much people love working there and how great it is. They knew they needed to influence their public image and advertising is how they do it.