Oh really? What makes you think the local unemployed resident who is in the out of state area won't do the same?
Because salaries depend on the Value of the Marginal Product. We are talking about areas where no competent workers who desire work are unemployed. If you go there and offer to work for less than the Value of your Marginal Product, you will be hired.
Again, here in SW Arkansas, there's not a big pool of people who want to work but cannot. In fact, the unemployment rates in the fall and winter are inflated by the presence of seasonal workers (loggers, construction) who draw unemployment during hunting season.