Looking at the World Record Players since 1990, you see where the money is.
1990: Roberto Baggio, Fiorentina – Juventus ITALY
1992: Jean-Pierre Papin, Marseille - Milan, £10m ITALY
1992: Gianluca Vialli, Sampdoria - Juventus, £12m ITALY
1992: Gianluigi Lentini, Torino - AC Milan, £13m ITALY
1996: Ronaldo, PSV Eindhoven - Barcelona, £13.2m SPAIN
1996: Alan Shearer, Blackburn Rovers - Newcastle United, £15m ENGLAND
1997: Ronaldo, Barcelona - Inter Milan, £19.5m ITALY
1998: Denilson, Sao Paulo - Real Betis, £21.5m SPAIN
1999: Christian Vieri, Lazio - Inter Milan, £32.1m ITALY
2000: Hernan Crespo, Parma - Lazio, £35.5m ITALY
2000: Luis Figo, Barcelona - Real Madrid, £37m SPAIN
2001: Zinedine Zidane, Juventus - Real Madrid, £46.6m SPAIN
2009: Kaka, AC Milan - Real Madrid, £56m SPAIN
2009: Cristiano Ronaldo, Manchester United - Real Madrid, £80m SPAIN
2013: Gareth Bale, Tottenham - Real Madrid, £86m SPAIN
The 90ies: Italy broke the world record again and again.
The 00ies: Spain broke the world record again and again.
The 10ies and 20ies: England will do it (and Real will fight back because of... being a circus.)
Then China or so.
So my guess:
Griezmann to City.
Kane to Madrid.
Neymar to City.
Müller to United.
Honestly, I have no clue. 4 years ago, nearly no one would have said Pogba.