We have had wild hogs inhabiting most of southern Texas for as long as I have been hunting, dating back to the late seventies. However, the population "seemed" contained to what is referred to as the South Texas Brush Country until the 80's. It seems the population reached as tipping point and began gradually spreading north and east where there was actually agriculture, more prevalent surface water and better overall range conditions. this exacerbated the spread of feral swine like pouring gasoline on a campfire...
The notion that hunters are responsible for the spread of feral hogs is just silly. Sure, I would imagine some isolated populations resulted from transplantation for hunting purposes - maybe even large local populations. However, I think the head of the task force on feral hogs in Texas said it best: "There are two types of landowners in Texas and the rest of the South below the so-called frost line. Those who have wild hogs on their properties and those who are about to."
Where I live, wild hogs are not really viewed as much of a problem. Sure, they root up hay fields and gobble up corn beneath deer feeders. However, there is very, very little commercial agriculture outside of a little cotton and grain sorghum in isolated pockets. This country is completely covered with pigs and we have plenty of deer, turkey and other game. In the end, pigs are more a "nuisance" species that happens to taste pretty good.