I imagine like most people his motivation has several dimensions of which money is only one. He probably wants to win things, play at the highest level, etc. And sometimes all those incentives are aligned and sometimes they aren't. When you are at the top of your game, like say Grealish, then they probably are if you are still developing then there is a trade-off to consider. So even if maximising your lifetime income is your objective, you still need to build your human capital to reach that peak. And to that you need regular game time in an environment that allows you to develop. For perhaps the first time in my lifetime Sunderland is one of those teams. Swaning off to somewhere has risks. You can go to a massive club like City and stagnate. He can ask Roberts what that was like and how that almost derailed his career. Or he could go to Burnley, a club which like us may not be the height of his ambition, get the game time but struggle in an environment which is more restrictive due to PL competition. It may suit him, and he might develop faster, but its a risk. These players have such short careers that these risks are huge. We know he is happy here, he gets game time, we play in a way that showcases his talent and he is getting better. He has 3 yrs left on a contract. That's good for us all round. Another year to develop and then that will be the time for player, agent and club to decide whether he stays here (probably on a new contract) or he moves on at a time where the club can still financially profit from the improvement in the player that they have been responsible for.