In the end, this is also bad for the employer. Once someone discovers they've been underpaid for so long, the trust is gone. As in the article, a raise to an ap

In the end, this is also bad for the employer. Once someone discovers they've been underpaid for so long, the trust is gone. As in the article, a raise to an appropriate salary doesn't change that. You're going to lose that employee, who has proven for years to be valuable, has knowledge of all workings, etc. Training a new inexperienced employee is always more expensive.