IMO that's a £50m gamble not worth taking. Especially as he won't be doing these great things with us regardless if we refuse to sell as he obviously isn't going to commit to us long term. This lad isn't going to be a world beater and give us £50m worth of production in the two years he has left with us.
It is because he already is a darn good player.
He already averages more dribbles than everybody in the league bar Hazard.
He has already proven he can contribute in a title challenge team when he isn't the main player but rather a supporting act, something he will be at all of the other clubs being linked with him
He is already a very good player, he isn't a striker, he isn't an accomplished finisher yet, but at 20 he has already shown he can be devastating.
And if he doesn't work out, you can sell him for 30 m in the next two years, the same price 26 year old Willian with 4 goals and 3 assists to his name fetched.
The price is fair.