I think it really depends on the situation. If all 3 above are applied, 'pay' might still be a requirement (maybe someone is starting a family, maybe they got a

I think it really depends on the situation. If all 3 above are applied, 'pay' might still be a requirement (maybe someone is starting a family, maybe they got a way better offer) but having them in a position that they like will at least guarantee that they will probably talk to you first. If I, as a dev, really enjoy my job and know that I might not get a better situation by switching, I will at least ask my employer for a raise before walking. All in all, money is the easiest thing to fix of those in my opinion and it's easy to talk about it.