[czl]

Wages must rise to simulate local supply. If instead a foreign worker is hired and wages do not rise the local supply is not stimulated and the foreign worker being a short term solution causes a growing long-term problem: a growing inadequate local supply of high skilled labor.

And if foreign workers are a "better deal" because they take more abuse (due to terms of their immigration) this further disincentives fair competition and makes the long-term problem larger.