Agents always wants the best for their players financially, they only think about the money side and that is their job so it makes sense. However, football isn't just about money and it isn't about your future income, sometimes it is about loyalty and sometimes it is about the wins.

If you are going to go to some Saudi league and make 200 million a year, then yeah financially that makes more sense, play there for 3 years and come back and you will have more money than you ever dreamed of, and then you can chase success later on. An agent needs to tell the player to do this, because that is what he is hired to do. It is the footballers job to tell the agent no, because if he wants to stay then he can stay, doesn't mean agent is doing something wrong.