The line of advice should've been "Nobody wants to read your shit if you're trying to sell them something". And even then it would've been half off imho, but I can't come up with anything better.
Some of the highest voted articles HN don't follow any of the detail advice in this article. But they're popular anyway, because they're interesting. Somebody made something cool, and people want to know how he/she did it. Sure, these only work in niches. When you go mainstream, the only articles that get read by many are "10 ways of getting your partner to gave sex with you more often".
But hey, this is an advertiser. What does he know about niches? More yet, what does he know about people who are actually, genuinely interested in a whole range of topics, and would happily spend 30+ minutes reading a single article?
Of course, any article an benefit from being fun and concise. But that's just bonus, no prerequisite.
Because if you've got something interesting to tell, people want to read your shit.