Immigrant Workers

Alot of construction business owners like to hire immigrant workers because they'll work for less and they often work harder than the average american. An article published on businessweek has an example of a business owner who hires immigrant workers who hold a H2B Visa that allows them to work in the US for 12 months. Every year this man pays his lawyer and other fees to try to keep these workers here. The article stated that most times he ended up understaffed and had to pay regardless. I don't understand this way of thinking. These business owners think they're saving money by hiring immigrant workers but to me it sounds like its costing this guy more money and causing more stress. I know americans can be lazy and most don't want these kind of jobs but maybe they'd be more willing to work if they were paid better. I think these business owners could afford to if they can afford a lawyer to pay for immigrant workers. But what do you think?