Sure, that’s obvious. The problem is the tons of content that isn’t easily associated with a product or service. Like news and opinion (many of the article’s examples are from The NY Times)
There's books about everything, sure. It doesn't mean this approach is profitable enough to support the news gathering in the first place.
>more relevant option than someone's ass
That's a pretty low bar. I'm not arguing for this kind of ad. I'm only saying that keeping all ads exclusively topical would be highly unprofitable for many categories of information you find on the internet.
>News about crime -> advertise a home security system
That would create some pretty perverse incentives for news organizations to fear monger about local crime (more than usual that is). What could go wrong?
Opinion piece about politics -> advertise a book of the same political leaning
I guarantee, no matter the topic, there's always a more relevant option than someone's ass.