Look, in war times, we can plant potatoes in all our gardens and take our spare meadows. We don't need these farmers in peace time; we really don't. They are leeches.
Of course, a lot of that had to do with incentives....
If you only grow and eat potatoes, you can feed 7 people 2000 Calorie/day diets all year. That's the figure if you grow potatoes like big potato farmers. If you nurture the land and integrate other species taking advantage of differing growing seasons and do all you can to make perfect soil conditions, you can get a lot more out of it than potatoes every day for 7.
Norwegian farming policy is focused on maintaining near-independence in the food supply because the British embargo during the Napoleonic wars in the early 1800's is still seared in the collective consciousness. E.g. every Norwegian primary school child will go through the very long, very tedious poem "Terje Vigen" about a man who tried to evade the British embargo by taking a small boat to Denmark to get food to feed his starving family.
Starvation happened despite farming most of the available land.
The concern of local food production rose to prominence again during World War II, when German occupation meant strict rationing, which led to "fun" food innovation such as flour substitute made from bark, as growing vegetables etc. in your back garden simply doesn't produce enough for most people to sustain a family.
But here's a summary of the end:
He is released from prison at the end of the Napoleonic wars, and comes home to find his wife and child died while he was in prison, and were buried in a paupers grave.
Years later he comes across a ship in distress and it is the captain of the British ship that caught him, with his family. He threatens revenge, but on picking up the child changes his mind and saves all of them.
Don't mistake me, I'm not claiming that Norwegian farming policy is perfect, merely that it does seem to work at the moment.