It's a pretty narrow niche. Assuming a 5% cut from Amazon, he's making 10 to 50 cents for every conversion.
Each article is costing him $50 or so.
So that article has to convert 200 times before it breaks even. Assuming 1% conversion, which is very optimistic, you would need 20,000 visitors to that page.
Ignoring the costs, 200k visits a month would turn $500. 2M would turn 5k.
It's pretty easy to see this isn't going to pay the bills. He didn't seem to do the math.
The most important thing in that comment is - for the first two years, the site made no money. Then one of their quizzes went viral.
Maybe this person gave up too soon? The keto site looks good and is useful, maybe if it sticks with it, it might make decent profit?