So they want to bring in someone and pay them more? Doing the same job? At the same level?
Then the guy might have a legit gripe, but such is rarely the case.
However, to be fair, at my last job, I was salaried, and my boss was a backstabbing assclown. After I made it clear I wanted to go back to the field (and he actually signed my request SIX MONTHS LATER), he had to go through the job selection process within my company. I was promised I could go back as soon as I had trained my replacement. It was soon clear that they were going to have to hire TWO people to cover my loss. ****up number one right there--they could have paid me more and I would have taken it, but nooooo....
I was more qualified, knew more, and had better rapport with the field crews than anyone he could have hired. They interviewed five guys (all techs, which is what I used to be), made offers to the only two guys who passed the interview. He offered them BOTH MORE MONEY THAN I WAS MAKING. I am not joking--I would have been TRAINING guys on a system they should 1--already have known, 2--and they would be making MORE than me.
Between that, the politics, and his little clique he promoted at the expense of ****ing over anyone NOT in his clique, I'd had enough. I interviewed with my present employer, and they offered me a job THAT DAY. Granted, it was for a lower hourly wage than I was making at the time, but given the fact that 1--CA versus NH cost of living difference is not insignificant, 2--NH has NO state income or sales tax, and 3--I now got paid for all the overtime I was working whereas I hadn't at the time, and I figured I was actually increasing my REAL income by 15-20 percent, and that money went MUCH farther than the same dollar amount could ever hope to achieve in CA.
I turned in my two-week notice and the boss didn't even want to do an exit interview with me. His loss. I ran into a coworker of mine late last year in Washington who also used to work in the same group. He told me the boss was beside himself scrambling to get a couple of college kids with no field experience to do my job, and they were failing miserably, making him look like total shit. The word, people, is schadenfreude.
Bottom line--if you're an even halfway competent worker in your field with even a modicum of motivation and you think you're getting screwed over, first fight for what you believe in (tactfully, of course), and failing that, take your talents elsewhere where they WILL be better appreciated.