My dad owns a mid-size landscaping company in a medium-sized city in the Midwest. Until the Great Recession hit, he'd hire around a hundred of laborers from Mexico and Latin America on H2-A visas every year. He could only do so after proving that they could not hire enough Americans at a reasonable wage (obviously, the meaning of "reasonable" is hotly debated, but at the time, it meant slightly higher than minimum wage). I've never understood why similar restrictions aren't put on H1-B visas.