From all I know, a firm bringing H-2B (farm labor) to an actual farm is what an H-1B bodyshop to a software development shop: it does not produce any farmed goods and its customers are farmers, who don't have legal departments. It's a middle man. A surprising finding would have been if such a firm started to hire Americans all of sudden: how would they sell them to the farmers if farmers could have just hired them directly?
Hiring? No, farmers can hire help themselves. Driving? Could be, though these firms, consisting of an immigration lawyer and a "CEO" are not likely to drive anyone. Either way, it's besides the point: the study found that middlemen specialized in re-selling foreign worker labor are not hiring Americans, as they never were planning to do anyways.
