120m is too high a fee in itself.
I dont think Dortmund, a selling club, would be doing themselves any favours if this true. Young, up and coming players might think twice about joining them if they start making it too difficult to get away and choose Portugal instead.
Yeah, because the large volume transfers of Dembele or Pulisic really scared the talents away, right...
Of course Dortmund take the signal nature for other talents into account. It is the prime reason why they are even willing to let go one of the best players with two years left on contract. Pretty much every club higher in the pecking order would not even make this concession. They would simply point towards the contract and shut the door right from the start.
It is not like Dortmund has become the prime destination for world class talents because of chance. They play CL pretty much every year (most of the time into the KO phases) have a state of the art training environment, play well flowing attacking foootball, have less media exposure than elite clubs, more patience with young talents and most importantly a stellar record of shaping top class talent which has also to do with the large amount of experienced high class players in the squad. Even players with enourmous talent will profit by training and playing with players like Hummels, Witsel or Reus.
Sancho himself consistently sang praises about his special connection to Marco Reus and how much impact playing with him had on his development. Talent development is so much more than just throwing youngsters on the pitch and letting them play. You need the right set up to let them thrive and Dortmund crafted this setup from the ground up and continues to nurture it. This is also why for every top talent like Sancho, Haaland, Bellingham they sign established players like Witsel, Can, Meunier alongside them to have a solid spine to develop the talents around it.