I grew in a family where we were self-sustained on potatoes. We had ~250m2 plot that yielded ~1200kg every year. More than enough for a family of 6, so we gifted/sold a hefty amount too.

What article doesn't cover is the amont of hard work required to sustain such garden. At least we had a two-wheel tractor that tremendously helped with planting, bushing, weeding and harvesting.

Harvesting is not a final step either. You need to let it dry, clean from soil and probably sort by size to pick ones you will plant later. You need a pretty big, cold and dark storage for over a tonne of food. You need a way to transport it to your kitchen. So work spent by us only on potatoes was ~400 man hours each year.