Klopp says that the club must make it difficult for players to leave.
https://www.mirror.co.uk/sport/football/news/jurgen-klopp-wants-liverpool-club-11890539
Well, there is a straightforward solution. If we don't want an important player to leave, we pay him what he is worth in the market. It is ridiculous that some do not realise this. Take Can. He is on apparently £55k a week. His worth is probably at this time more than £40m as he is young. In 4 months time he'll be gone and this money will be lost (and an equivalent replacement will need to be found) and on top that player will probably be paid double by his new club.
So, why not factor in the signing on fee that he will get by signing for say Juventus (£10-15m) and the wages he is worth say £100k/week? Which means wages of £160-£200k a week. And the club will still in profit as it won't need to fork out £40m plus for a replacement together the big hike in wages.
AND if he plays well, he'll be worth £60-£100m in 2 years time when Barcelona comes calling
If some players are financially illiterate, their agents are certainly not. And clubs like ours should stop thinking they are by offering these players way below what they will get by leaving. Same with Ozil at Arsenal. They offer to double his wages but if he leaves he gets three or four times that amount. Wenger says he is so surprised they want to leave.