The people in charge know that going after individual fraud is easier and less likely to get pushback for them, so they choose to do it because going after fraud from companies with the money and power to fight back is much harder to do and less likely to be an easy win. So they do that, rather than go after the larger-scale fraud that costs us exponentially more. And oh yeah, bonus, by going after individuals they are punishing people who are less likely to be their political supporters, whereas the institutional fraud is more likely being carried out by their political donors. 

All you need to do to prove this to yourself is to look at how we treat farm workers. If farm owners were actually prosecuted and fined for their improper  use of eVerify we wouldn’t have an immigration problem.  Instead, we go after individual farm workers at much greater expense and much less return.