Again in an area like NYC, South Florida, and Phoenix, there are more low-level service jobs than their are natives to fill them. This is not the case in upstate New York, western Kentucky, or rural southern Ohio, but that has more to do with the lack of dynamism in the local economy than anything else.
It may also have to do with supply and demand. Illegals mostly from Mexico are going to open more ethnic restaurants, which in turn requires more workers. This area on the other hand will only allow that amount to thrive which can support the smaller market. Without illegals that would most likely be the dynamic throughout the country.
Which is why we need REGULATED LEGAL immigration in areas with labor shortages.
I've no problem either with legal immigration that's regulated and not excessive. The economy benefits from that as long as the immigrants are self-sufficient and not a social burden as illegals tend to be.