Because they can. You're unwilling to move to be paid more, or find a new job (which might be hard, as most companies are acting as a cartel). Look up BATNA,

Because they can. You're unwilling to move to be paid more, or find a new job (which might be hard, as most companies are acting as a cartel). Look up BATNA, and decide what you want to do about the situation - don't expect them to do anything about it.