Radiant Rosa

I'm wondering about how farming worked in Natanatan. According to the Coppermind, Navani's idea of creating a kingdom in the Unclaimed hills is discarded because it would be too hard to farm. We also don't really see any big settlements in the Frostlands aside from a few coastal cities, which implies to me there isn't enough farming going on for a large population base. I think something similar to the scouring of Aimia happened with Natanatan. The Natan had some sort of fabrial that made the area more habitable/farmable that eventually broke (either by disrepair or sabotage), leading to the destruction of the kingdom. Didn't see this idea anywhere and wanted to see what other people thought about it.