The freemium models of the New York Times and Washington Post are the ones that are cleaning up. You get a few free ad-supported articles a month to pique your interest, and if you are really into it, you need to pay a subscription. But Buzzfeed never had a brand people would pay for.
Buzzfeed, the non-news part, certainly knows how to produce cheap content, which makes it easier to ad support. They also do sponsored content.
But I'd hesitate to say that Buzzfeed understood the medium. They knew how to game traffic. They didn't know how to make money.
A lot of news outlets chased clicks. They thought they understood the medium. Making money and supporting yourself is the ultimate understanding the medium. Turns out The Gray Lady understands it the best.