I had the pleasure of arguing for a team members promotion once (ie a raise effetively). The domain our team of 5 worked in was pretty challenging (heavy algorithmic stuff). I spent a year trying to train up my team, and although they improved, I still felt like I had to do the hard stuff myself. With the exception of one developer. For example if a project was particularly hairy or the time frame was too short, it was either me or him doing it. And I couldn't give him all the hard stuff so I ended doing a lot more coding than I had time for.

I went to my boss and said, X is carrying my team, he does more than any two other developers combined. He needs a raise, I can't lose him! And he got it.

If you got someone who's good, that's what it boils down, either play ball or lose them.