That's probably because all those farmers own land and farming equipment. So it has a lot of net worth (capital), but return on capital isn't very large. It's

That's probably because all those farmers own land and farming equipment. So it has a lot of net worth (capital), but return on capital isn't very large. It's kind of like people who have lived in the Bay Area for years and whose house is now worth a million or two. Yes, they are millionaires, but that capital is only useable (in the "I'm rich!" sense) if they sell their house and move somewhere cheaper. And if farming is your career, you'd have to switch careers to use that net worth, which is daunting and maybe not very likely to be successful.