Because no farmer ever will tell you he had a good year. He should have sold a month earlier than he did, or held on a week longer. Just the way it is, I guess.
In my business I see their books. Good years and bad years. Some things are more volatile - dairy can swing between losses and significant profits. Layers are pretty steady if you are on a contract, as long as you don't get the avian flu. Produce farmers rarely have a loss year, but their high income years are generally not as high as crop farmers, who sometimes do show a significant annual loss. More risk = more reward.
The last few years have been pretty good overall, for my clients.