Paris is an over rated team full of has been players and the money is what keeps everyone happy. I actually don't blame Mbappe for staying as Real Madrid have huge debt. They owe salaries to the tune of $203 million and was reading they owe more than 1 billion pounds in debt and actually use the transfer market in a way called outstanding transfer payments as they don't have the financial resources everyone thinks they do. Why you would call Real Madrid a stable financial project is so far from the truth and you must read up on how they are in so much trouble. Not as bad as Barcelona but they also are like a house of cards and La Liga will have to step in if they don't fix things very soon.
Real are doing upgrades on their stadium which actually helps them with their debt as it gives them debt relief from the League.