To the american high school:
I would not compare you to an immigrant, I would say 100% of them do not have such a good education you are receiving through public american school, so why compete with them for a $5-20 dollars an hour. You should be approaching better job standards as I suppose you have got a good education. Unless you are killing classes...
About the general questions, it is complexed, the matter is intertwined with others...as is capitalism.
It is a fact USA needs these immigrants which constitute part of their blue-collar employees, jobs, americans don't like and don't need to do considering high standards of education, so who would do these jobs: immigrants.Removing them would cause losses for american government as their basis would be damaged.
In the other hand, immigrants are not stupid, they can and they are working hard to learn more skills, get a business certificate, stuff like that and that would be a problem because would compete equally to americans and would not constitute a basis level but a higher one.
It's intricated, probably the better approach is a maintenance of illegal immigrants and tough immigration laws to secure USA future.