Maybe we don't know everything. I also read that Williams wanted a guarantee of a place in the team, but Flick did not want to agree to that, and I can understand him. The issue was that Williams plays in the same position as Raphinha, and he is worried he might be left without playing time. Though to me it seems unlikely, because there is no point in buying a player like that just to leave him on the bench. But if for the second season in a row they cannot reach an agreement with him, then they should forget about him. There are other players available.
You're right, and Raphinha is in very good form For Nico Williams, the fact that he stayed at Atletic is because he feels better there, and they give him much more security there, and if they were going to put him in Barcelona to put him in for the 70th minute or something like that, well, for him it's not worth it, and another position doesn't suit him. Barcelona has to look for another player, but for another position
Perhaps the absence of Nico Williams' transfer is a good thing for Barcelona. Raphinha is in really good form right now and has had a very good season. He could perform similarly next year. On the other hand, with their young star player Yamal, they've started using both wings in a very dangerous way. I don't think Barcelona currently has much of a shortcoming in that area; they could have done without Nico.