My general feeling is that a good field is usually the product of generations of work: where I grew up, you had to put drainage channels every two meters, giant ditches, endless effort to get rid of weeds, etc. It wasn't the case you could just move into unmaintained soil, especially virgin soil with shrub on it, and expect it to start producing wheat without a hell of a lot of labour.
That's compounded by the fact that farmers are basically soil-seeking missiles, and always have been. If there's a patch of really good farming land, that's probably been a lot of competition for it in the preceding centuries. If there aren't any farmers on it, there's almost always a reason.
Sure there would be crop losses to animals in such fields, but those animals also fertilize the soil and keep the microbiome diverse.
People look at a state like Montana and think that the vast stretches of land are undeveloped, but in reality, unless you went in with a lot of investment and care, the soil would just lift off and you'd end up with another dust bowl.
If Canadian farmers are like farmers in most of the western world, they're great at filling forms, exploiting bureacracy, getting paid to not grow sugar beet or whatever the latest scheme is, then yakking about how it breaks their cowboy hearts that the state can't just let them be free.