[durgiston]

I think this is inertia from the housing bubble in 2008. After that, companies didn't have a retention problem with employees because everyone was terrified of not having a job for even a brief time. But since then, the economy has recovered (at least for this fairly high class) and also the ACA means that (at least for now...) you aren't as dependent on your job as you used to be. So you can afford to look around, and all the employers have the money to pay you what you are worth. They just don't remember that they have to do it to their existing employees too. They have forgotten to pay for retention, and I suspect that barring a new crisis (which I admit is more likely now) employers will start to realize again that retention is cheaper than searching for and training new employees