Perhaps it's not just the money. Some people are happy to stick with the same position, the same employer, throughout their career. You might call that a lack of ambition, or a sign of loyalty. Some people want to move on, after a long period in the same job; they want to experience a new challenge, or work in a new environment. You might that call that a natural thing, or condemn it as a lack of loyalty. People have different feelings and different motives. If they've done a good job and generally behaved decently, they deserve our respect. N'est-ce pas?