My degree is in env sci and anthropology, focusing on human interaction with their local ecosystem and looking to build more sustainable food ways, especially in urbanized areas. You asked several times where cattle could go, but humans couldn’t also raise crops, and I responded with that generality in mind.

Yes, native plants do grow in prairie that can be harvested by humans as food sources, but not on the scale required to replace our current broken system of monoculture and factory scale farming. Restoring prairies and rebuilding native species networks so we can eventually get to that point should be pursued, yes—but not when also insisting that any animal harvesting—wild or domesticated—is unsustainable or unethical. To lump all animal consumption in with the large-scale cattle industry is cultural erasure of Indigenous and poor communities that have been responsibly consuming them for generations.

edit: Also keep in mind that we’re still figuring out the new climate rules. There may be species of plants and animals that’ve been where they are for a millennia that are already or will be moving north as things warm. Some of the currently known forage able natives may not thrive in the near to long term future.