That said, I think this vastly overstates how much people got their food from trade. Spices and some goods were, of course, big in trade. Mainline food? Not so much. Most people were not able to stockpile large quantities of food. Some cities maybe could. But it would have been grains/seeds or actual live stock. Not meats or anything that needed refrigeration. For... well, obvious reasons. Even cured meats typically have a very short timeline. So, fishing and hunting and basic gardening would have remained something that people had to do. Pretty much everywhere.
And indeed, this is inline with your edited in article. What were they trying to trade for? Corn. Why did they need to get it by trade, because their crop was bad. Why was the trade not working well? Because nobody had excess corn to trade. Long term stockpiles just couldn't exist to the scale that we think of today. And a lack of rain meant everyone was having a bad crop.
Finally, I want to be clear that I'm perfectly comfortable with the idea that I'm just flat out wrong here. I've just grown super doubtful of a lot of the "these morons were able to sail across the atlantic, but were too stupid to do anything that would have resembled living off the land." Despite most living at the time looking like what we would call that.