I was reading "Hog Ties" again and came across an interesting part about people who raise pigs.
Horwitz asks David Meeker of the NPPC (National Pork Producers Council) if their members are any different. Meeker explains that pig production is a profession without glamor, unlike cattle. Google Books has that page available for reading.
Cattlemen get to wear cowboy clothing with fancy metalwork, ride around on a horse, rope steers, etc. They get glamorized in movies and commercials (like the Marlboro Man). They get to fly out in their private jet to their ranch to check on their cattle. They like wearing their expensive cowboy clothing, riding around on expensive horses, buying and selling expensive show cattle, etc.
This phenomenon is a bit like "hobby wineries" or "vanity restaurants" (or hobby farms) - you've got market participants willing to accept low returns because of the non-monetary returns they derive from being in the business.
When we finally have the technology to turn things like corn and soy into milk-like and meat-like substances (without actual pigs or chickens), I think we'll see chicken farming and pig farming collapse, as most people switch to low-cost meat substitutes. E.g. instead of feeding grain to pigs and chickens, we might feed the inputs to cells, who will produce the meat directly. Maybe we'll achieve the same with milk, and eliminate the need for dairy cows.
Based on what meat dominates the American market now, I don't think there will be excellent meat substitutes soon. So even if we get in vitro meat, I think you'll still see people raising Wagyu cattle and Mangalitsa pigs, even as cornish cross chickens and standard pigs vanish.