You say “I spoke with a Hassidishe shochet who trains in ofot and he said that for unmarried men and non-Satmar men, it is enormously difficult to get any work, since Empire and Rubashkin both use Nirbarter hashgacha.”
One of you is lying (Or more likely rthe story is made up). The facts do not support this in the least. (regarding non-satmar) There is a long held minhag not to hire a bochur as a shochet. Nothing to do with Satmar.