There is a price point for every single job in the entire world. If I advertize for roofers at 8/hr I will get no one to respond . If I advertize at 60/hr I will get 100's of applicants. The roofing contractor has to find the correct price point which is a number between 8 and 60. That is his job. Not undercutting the indigenous labor force by introducing scabs from the third world into the equation. That is simple corruption and lawlessness. Again I have to explain markets and economics to you.
IN theory, yes - but it's not nearly as simple as you say it is. And price is only a part of the employment picture. The biggest perverter of your theory now is the lifestyle you can live by not working. That has artificially raised the "price" of certain skills to more than they're worth to the consumer. Never forget, a consumer has to pay for every job ultimately.
The other issue is the willingness to stay with a mundane job for a long time. This is not in the American psyche to do so. Some of that is good by the way. Some of it is laziness. That is bad.
In your roofing example - 8 is ridiculous. If you think the hispanic population - legal OR illegal - is working for 8, you don't know the market. Maybe in a tiny town, but not very often. And the consumer will not pay the 60. The problem is that in roofing, say the skill is worth 17-20.....but you can live a 25/hour lifestyle on the goobermint dole. There IS no workable price point in this scenario...and this is the conundrum we are in, which is why this will never get solved without also addressing our welfare and educational issues.
You and I agree on almost all of this...philosophically. We just have different perceptions of the reality on the ground. By the way, this reality drove me out of this business for the most part. I don't like it. But I have put my money where my mouth is. I live the fall out.