If he paid enough to entice Americans ($20 per hour?), then he wouldn't be able to charge his customers enough to cover that cost and would go out of business. That's what I'm basing my opinion on. 

It might be driving down wages in some areas like landscaping. The real issue is that pay for low/middle/upper middle classes hasn't really risen in the past 20 years. It's not illegal immigrants working in the new Aurora Amazon warehouse for $12 an hour. Those are American workers, working for slave wages.