Yep, I see this in industrial automation. My company is particularly bad about it, since the corporate office is in Houston where you can hire people for the duration of a project fairly easily.
Problem is, my part of the company isn't in Houston, so qualified employees are hard to find. So we need to hold on to people, which is hard when we rarely hand out raises. I do my best to train up my guys, but I know that they're probably going to move on in a couple of years. My goal is to make an enjoyable environment so that they'll come back eventually at a higher pay rate.
My best worker - the one I'm training up to be a lead - is the lowest paid member of the team, and I can't do anything about it. It sucks.