PSG are very optimistic that Mbappe will sign a new contract with them but if in anyone he didn't then I will think the board and management of Paris Saint Germain are very stupid and have no value for money and are not good business men,and are full of pride, but I think the reason Mbappe wants to leave is because he is tired of the competition of the French league,he has been there all his life he wants to taste something different and he also wants to follow the path of benzema
Mbappe is new rising star of soccer world, and he has right to complete his dreams as if he is like to join Real Madrid then surely money is nothing with this all and currently PSG is surely had no good charm in French League, and they are fail to have a good winning combination for Champions League which is also matter for him, so he is feeling to go for his desire club and enjoy his game with some good wins.
Now, we all watching he is refusing all calls from coach and owner about signing new contract mean he is going to leave and money can't stop him for doing this all most chances we will watch him in next season playing with Benzema in Real Madrid jersey and having some good matches against teams like Barcelona and Atlético Madrid.