"I'd have taken that over my summers in college - but, unfortunately, English-speakers (anecdote - not a blanket judgment) tend to get harrassed out of the jobs, from what I've heard. "
I was going to write a detailed answer but this is easier.
Find out where your local illegal bar is, go there and have a few beers(if they serve you), Most of the guys on the INTERNET don't have the courage to do that, what they will find is a violent knife culture, men a few years older and a little more worldly than the young Americans that used to perform their jobs.
If anyone is brave enough to try this , try to make it an hour, well, the vibe you feel is what happens on the job site after the numbers shift, to where they don't have to play nice anymore.
The average 20 year old American is not ready to compete with a 25 year old man that had the balls to smuggle himself into the richest most powerful country on earth, and that has the type of mind that makes him comfortable dealing with challenges most of us only see in movies, like purchasing forged federal documents and living under an assumed name, always being prepared to jump out of the vehicle and flee for the border.
In time they figure out how to buy homes ,circumvent the tax system, raise families with all the health care and education, all while living undercover.
These people are just a little more than really sweet peasants, hoping to pick your tomatoes and then return to their village after they get their deposit back on their apartment in Chicago.
Gotta watch out for those violent knives. They are first cousins to those guns that go on rampages.
In Redwood City, CA (the heart of Silicon Valley) it's a gun culture. There was recently a multiple homicide in one of the local bars - all perps and victims had hispanic surnames. The bar itself is a dive.
Never even made the front page of the local papers. If it was white people dying like that, it would have been an ongoing "tragedy" and still in the news with ongoing analysis of our violent culture, etc.