At an airport where there are several flying schools competing with one another, there are those who pay their instructors fairly and legally, and those who are exploiting their instructors. The latter are often cheating on things like super and compo also, and as a result have an unfair commercial advantage over the others who are doing the right thing.
If the instructors are going short because the bosses are collecting huge profits then that is wrong. It is possible to stay profitable and pay the award. It can be done, but not if you have too many spare instructors sitting around.
If people go around undervaluing themselves by begging for work, they are asking to be exploited.