This can easily happen when you sign old players who won everything only because you offered more money than any other team. Plus they know their season in France doesn't really start before February / March. Of course this can still work out well for PSG but Premier League teams can't afford it.
Indeed
PSG is obsessed with signing top players past their peak... I'm pretty sure they will go for the likes of Benzema,De Bruyne,Kroos, Lewandowski,etc once their current teams don't need them anymore, and let them leave.
But i get why they are doing it, no way the likes of Messi,Ramos,Buffon, Benzema,Kroos, etc would be down to play in Ligue 1 at their peak...so they have no other option , but to wait for top players to get a bit old in order to get more chances of convincing them to join PSG.