Sadly, money talks and drives many people. Those with immense wealth often want to grow their immense wealthier even more - it's like an addiction so to speak.
As you say, he's not even your typical top tier professional footballer: he's earned mega bucks from a very young age and will continue to do so at PSG or Real.
If he goes there, it's pure greed and shows more about his overall motives rather than any love for the game. Look at the current contract impasse...
... look at how he's built a situation at PSG where he had a huge hand in the club's running. If he gets big money and big power, I think he will take it.
In reality, he could easily come to the PL or La Liga on a very lucrative deal to play at the highest level, but is that what the real driving force in his career?