The thing about oil money is that oil money is , in effect, what bought VVD and Salah.
PSG bought neymar for a billion pounds or whatever it was and this was used to buy Coutinho. Without that money they probably wouldn't have got either and would still be waiting for Benteke to come good.
Also another point is that without oil money then a lot of the players out of Aguero, Silvas, Kompany, Sterling etc would have joined United who would now be on league number 25 and European Cup number 6.
Obviously Salah was bought before coutinho. Still though, £50m of oil money for sterling.