I do wonder how much that demand would still remain if the workers became legal workers.
The demand for illegal workers will not change if amnesty is given to those that are illegal now. The reason employers hire illegals is cheap wages, few if any benefits, and they will tolerate unsafe or otherwise undesirable working conditions better than legal workers. If we gave all illegals citizenship tomorrow- the new citizen workers would not work for low wages, etc and would move to better jobs. Their employers would be looking for a new crop of illegals to exploit. That is why amnesty is not a solution.