It doesn't have to cost. that's the part I don't understand. I hunted a farm in western OK and that guy didn't know me from Adam. Verbal agreement. Responsibilities were laid out up front. Don't follow the rules, don't come back. It's really simple. Written agreements are better, naturally, as there is a paper trail of responsibility with legal repercussions available to the land owner.
As far as the struggling bit, if a couple of thousand dollars is going to make or break an operation, they should probably consider selling the farm and finding a 9-5.
The states don't feel that the hogs have a retail value (they cause billions in crop damage and insurance pays for that) and at the rate things are going, most will end up following Missouri's lead. I know that Oklahoma is considering it and at least one state that didn't have hog issues has already banned hunting them. Hunting them for profit will go by the wayside as states are starting to regulate the movement and release of wild hogs. In any case, those who profit from it don't want the hogs eradicated as it cuts into profit margins and that's not in line with the reasons land owners want them gone.