As an observer with a front row seat at Ground Zero of the effects of decades of excessive immigration, I have some observations to share:
Immigrants aren't just here picking crops and scrubbing toilets anymore. Not by a long shot.
Once upon a time in California I remember entry level jobs, and affordable housing. As Mexican immigration increased, I couldn't help to notice that those things seemed to decrease proportionally. I watched it happen.
There is no labor shortage. When large labor intense companies (FedEx as only one example of thousands) stop treating their blue-collar workers like garbage, then you will know there is truly a labor shortage.
If you think that any savings that companies realize due to cheap immigrant labor are being passed to the consumer, I've got ocean front property in Arizona to sell you.