A lot of print magazines, like Vogue or even Field & Stream, are like 60% or more full page ads. But if you’re reading something like New Bride magazine you’re probably actively shopping for wedding dresses and flowers and such, so the advertising ideally works as part of what makes the magazine valuable for the reader and the advertiser.
The real problem is that the finance and business folks are addicted to performance metrics and they preferentially put their money towards things that can be represented as graphs because it’s hard to argue with a graph. Jon Gruber has a vague sense for what sort of audience he has and what they’re into, so he can pitch advertisers on the idea that by advertising with him they’re going to reach an audience of Apple enthusiast technologists who presumably care about design and UI/UX and whatever other intuitions he has about his readership. But none of that is a quantitative metric, so only a small market is open to putting money into it.
This very direct, very personal connection to the web business doesn't exist in most other sites.
I think a lot of online publications could be modestly sized businesses with a very respectable annual revenue range in the tens of millions or even hundreds of millions, but they erode their own brand value chasing tantalizingly higher numbers that SEEM in reach but actually aren’t.
If I want to know something, I will search for it. The sites that offer the info could easily choose to show ads specifically relevant to the topic at hand instead of hiring out that task to a cyberstalker.
I don't want to see ads for pet medicines on multiple sites because some algorithm has decided that I have a pet in need of medical assistance. I don't have a pet at all.
I'm sure I only get those because I'm using apps to poison my digital footprint, but my ex-gf, who didn't and did have pets, probably got my home IP tagged as a pet owner.