We'll the military took me to the NE, mid-atlantic, Florida, California, Hawaii, and Alaska and I grew up in the PNW so I'm not really "from" anywhere but have lived almost everywhere in the U.S. I've actually known quite a few migrants, both legal and illegal, I wonder if you have? I'm also an entrepreneur with a decent size payroll, so I know that no matter how many dependents you claim you still have tax withheld. And it just so happens that my first startup ran auctions, so I not only have a few econ classes under my belt but have actually seen the supply and demand curves in real-world action. So have I "ever thought about supply and demand"? Absolutely, I could write a fricken book on it. And I'll tell you exactly what would happen if every immigrant fruit picker disappeared. Let's say the farmers eventually pay the amount necessary to compel someone who could otherwise be assembling cars, working at a restaurant, or some other blue collar job to switch to one of the absolute worst jobs in the world. The price of pretty much any labor intensive farm crop would double or triple. And that would cause two things. First, classic supply and demand curve, the demand for those foods would go down as price went up, although the curve for basic food is relatively inelastic. We'd basically stop eating fresh fruit. Which would have a far bigger negative impact on jobs, from the farmers to bakers to restaurateurs to ordinary consumers who spend more on fruit and less on other consumer goods to the people who make those other consumer goods that people spent less on so they could buy enough oranges to avoid the scurvy. Second, we'd start importing most of our food. Neither of those are good for the U.S. economy as a whole or your typical reflexive immigrant hater for that matter. Something to think about, if you're into that whole thinking thing.
I'd note that again you produce a bunch of unsubstantiated anecdotal evidence that isn't even your firsthand anecdotal experience, it's what you picked up in your echo chamber and never thought to actual check. I've provided real numbers, you've provided "I claim Mexican" and a completely unsupported claim that undocumented immigrants are en mass risking severe criminal penalties to "work in one name and claim welfare in another name while scamming the tax system". And not sure where you relative is in California, but when I lived there contractors were making $75/hour and up, and it was damn hard to find one who wasn't booked for months if not literally years. If your relative is out of work, there's a reason and it has a lot more to do with either their lack of business savvy, quality of work, or laziness than it does some mythical amigo. Nice to have a boogyman to blame though, wouldn't want to take any personal responsibility would we?
I'll extend the same offer to you as I did to the other guy who was apparently so terrified of it that it reduced him to middle school insults. Come work in the fields with me for a day. Just one day. Then we can have an intelligent conversation.