US citizenry needs education on immigration first. Then we can see where adjustments need to be made.
How many degreed university graduates do you know in the US that will work 6 & 1/2 days per week, two of which begin at 5 a.m., the others at 7, no recognized holidays, running pressure washers to clean birthing pens in commercial hog farms? Among other rather discusting duties. Ever shared space with a sow in labor? These are the types of good jobs that are recruited from other countries to the US for limited time employment.
Don't think for a minute that all the foreign faces you see daily came totally on their own accord and are undocumented.