When other clubs don't have any good youngsters, La Masia graduates never end
And I think Barca doesn't want to lose Yamal, Pedri, Gavi, Balde, and Cubarsí.
They are part of the next generation. Barca cannot give up or let them go, they know the Consequences.
They are a good player with big prospects and currently mostly on low wages, there is no sensible reason to sell them, both sporting and economic. They are the future.
It is not up to Barcelona alone whether these players are going to stay or not. Barcelona has been smart though when it comes to most of the contracts of their youngsters. By giving them a chance to play for the first team in La Liga, one of the conditions is a long contract duration. But these durations of any of those contracts aren't without limits. Some of the players have release clauses and if they sign a 5-years contract at the age of 18, by the time they turn 23 Barcelona is getting into trouble as the players get into a more powerful position for negotiations. None of these players would tie themselves longer to the club without any need for that to be done. Barcelona has been this club that all the players dreamed of, but times have changed over the past few years. If they want to make sure that their best young talents don't leave, the best way to do this is to become the best club in Europe again and that is probably not achievable in a short amount of time.