The greater the supply of something, the lower it’s cost. Labor is like that. If there is a lot of unskilled labor, then you don’t have to pay a lot for it. If it starts getting expensive, then one strategy is to lobby politicians to find an additional supply.
Wages for Maine citizens remain flat because businesses lobby for continued inflow cheap labor via immigration from abroad.
What is particularly galling is these businesses have managed a neat trick of turning this purely self-serving activity into a civic virtue, being praised by media outfits as humanitarians, when in fact, they are simply gaming the immigration system to keep wages low and privatize profits while socializing the costs of importing low skill labor.
The business owners do well themselves. Maine workers, looking for a job with good wages, and taxpayers on the hook to pay for social welfare, are out of luck.