It's worth noting most of this article is spelled out by Adam Conover, the ex-CollegeHumor star of Adam Ruins Everything. Generally speaking, the man does his research.
They were only "immensely profitable" because they were in an oligopoly with 4.5 players. Netflix disrupted that, and then it was a race to the bottom. Saying the "public enjoyed" network TV is a bit of a stretch, too. For the most part, it was just adequate.
Not adequate either. Throwing a hundred ads during one show, at the same time charging you for it and that's somehow a good experience? Netflix is a million times better and that's why they're still raking in money.
They may not have profited as much as they would have from cable, but the number of viewers seems to speak for itself. I know they aren't the HN audience but surely we can see wider than that.