The Mexicans who are sneaking across the border are VERY SKILLED people. Mexico is still far behind USA in manufacturing jobs overall. One of my former colleagues was offered a job in Mexico as chief engineer at 50% more salary than he was making here. Point is unskilled people have very bad situation in Mexico, but in US they can work in restaurants or hotels and make much more than in Mexico.
They pay Mexicans $5-$8 dollars an hour in this Country and the Mexicans think they're getting rich compared to the Mexican wage scale. Check the Mexican pay scale.. keep in mind their scale is PER DAY.. not per hour.