Petrodollar infusion is only a partial explanation for fee inflation. Many of the largest fees have been paid by Man Utd, Barcelona, and Real Madrid, and they're not funded with petrodollars. Some of those deals are recycling petrodollars (e.g. Barca spending the Neymar funds on Dembele and Coutinho, Liverpool then spending the Coutinho funds on Van Dijk), but many are not -- e.g. Man Utd buying Pogba and Lukaku and Di Maria, Madrid buying Bale and James and Ronaldo, Barca buying Neymar and Saurez). Of the 20 largest transfers on record (in Euros), only 7 are linked to petrodollars.