Maybe not wheat and such, but other, more hardy plants.

You can try to grow it, but good luck hauling the tractor, plow, and combine up that steep hill that only a sheep can traverse. It's not a matter of "can I grow corn in that soil?", as you can grow corn on a rock if you throw enough fertilizer at it. It's a matter of "can I grow corn at any kind of scale that doesn't involve tilling and harvesting by hand?" And for context, keep in mind that people are killed in tractor rollover events all the time as a result of trying to traverse an incline.

There might be something to be said about limiting confined animal production fed with our most fertile crop land, but the same arguments aren't relevant for all cattle production.

From an ecological perspective, you're not losing wild nature for agriculture, cattle are just displacing grazing animals which would have been there otherwise.

Her head of cattle to land ratio is some crazy number like 100 acres to a cow/calf pair. Could be less IDK exactly. Consequnetly she owns thousands of acres to feed her cattle.

There is not enough water there to irrigate non-native edible species over her thousands acre ranch. She'd drain every creek, stream, and river to make a farm happen there.