"The same people that did it before . . ." thats a rather vague concept.

History seems to indicate that service and "entry level" jobs were the domain of immigrant groups who took those jobs to support themselves and their families, provide educational opportunities to their children to move up the economic ladder. Surely you're not saying that the sons and daughters of legal immigration should continue working in the service sector forever.

If we only give visas, such as the HB1, to the best & brightest, what imigrant group is going to wash the dishes, pick the produce, or watch the kids?