If you're so pessimistic that you literally sell your conventional assets to buy a farm, your retirement plan must involve children or some community inheriting it and taking care of you in your old age.
But even if it doesn't, you're still probably ahead in your pessimistic scenario (e.g. surviving relatively comfortably until retirement age, instead of dying earlier in some kind of collapse).
My farmland pays a rent dividend on the order of 2-4%/yr and I don't even have to be there or even show up to collect it.
I bought my farmland because I consider it doing my part to preserve the planet. I'm a big believer in the future of locally produced food and more local communities in reducing emissions and _corporate wastefulness_. As a side benefit it will preserve my standard of living. I thoroughly enjoy steak and so do a lot of other people. Livestock, land, and gold have preserved wealth since ancient times.