Immigrants come here because they are offered jobs. Thy live on lower wages because that's what it takes, and it's more than they could make in their home countries. Just like Americans, they need to take care of their families and help their children do better in life than did they.
If we want to stop illegal immigration, we won't spend money on fences or border patrols. We would use the money to investigate and fully prosecute the individuals and companies who hire undocumented workers. If there are no jobs, there will be no undocumented workers.