With all the money they use for the prize, they did not have enough money to count how many slam each of the players won thus far! Djokovic and Alcaraz have number 24 and 5 on their cheeks. But so does Sinner, who should most likely have 4. Seems like a super jinx in view of the US Open!
BTW, there is literally no way to motivate players to go to play the ATP500 instead of this. The penalty for not playing enough 500s is much lower than the money they win even just participating into this, let alone winning it all. And they have to play a maximum of 2 or 3 matches.