I'd be interested in reading the source to see what the argument is. Off the top of my head, the Irish Potato Famine strikes me as a pretty real famine. It was certainly exacerbated by political pressures, and they were growing monocultures in the first place because of the pressure for productivity. But it was a real crop failure, and they learned to reduce their dependence on a single crop.
Certainly it could have been handled better, and far fewer people would have died. But I still think the death toll would have counted as a famine, or at best a famine barely averted by aid. I'd put it in a different category from starvation caused by war or corruption. Even the Great Chinese Famine could be chalked up to politics without too much of a stretch, but there are still crop failures due to drought and disease.
Since the agricultural revolutions of the past few centuries and especially the last few decades, we're so awash in food that aid will always be stymied by people rather than lack of calories. But I'd put the tipping close closer to 40 years than 400.