Also I think when you have a player who is still young but already established as one of the best in the world in his position the fee exponentially rises as you are not only buying proven quality, you are buying the opportunity to have that talent for more years than when buying players at traditional peak ages and you have a premium for the chance that they can still get even better.
So few players can offer that combination that their fees do seem very large (especially when they have a decent length contract behind them as well and are based at a financially sound club) - but I doubt Veratti for example would cost much less so top young talent is going to cost a lot.
Id personally not quibble about the cost to bring Pogba back but I doubt Thursday night football holds enough of a draw to get him to even consider it