> Animals also eat.

I'm curious: what do you think they were eating?

Livestock was and is used to convert plants humans can't eat into milk and meat that we can. Even modern grass-finished beef is raised mostly eating grasses. Grains are really expensive compared to some grass growing in a field. I don't understand why people think it would be even close to economical for a rancher to raise an animal over 1000 pounds on grain alone. That beef would be more expensive than any wagyu.