That makes no sense. Let's say that Verratti goes for 100 M,by which logic can you add Pogba and Ronaldo/Bale for that money?
I started this mess, so I will try to explain it.
This is what I would do if I would be a Psg's owner.
If I would want to strengthen my team, but I don't have the money or the rules don't allow me to buy before I sell, then the player who can go for the highest amount of money, and yet is somewhat replacable (and not a game changer) is Verratti.
Now, imagine Real paying 100M for Verratti.
Then, for 20M you can get a decent replacement, in let's say Gundogan.
He is not that good, but it is not as if Psg will crash suddenly with Gundgogan instead of Verratti.
On the other hand, Psg would have 80M left, and if they add 20-30-50M, they can buy, let's say Cr7 for 100-130M.
Their midfield wouldn't be that much weaker, and yet their attack and overall chances would be much bigger.
Anyway, no need to get into larger discussions about this.
My point was that I don't think that Verratti is Messi, the guy whom you would never sell, no matter what.