This story doesn't wash with me. Most malting barley is grown in areas that are too cold or too dry, or where the growing season is too short (Montana, Idaho, Saskatchewan, the Palouse of Washington and Oregon) for corn production. The two crops don't compete for space on farms.
We used to grow corn and barley , wheat, oats and flax too,, look like some folks in my old stomping ground still do in Minnesota ,