Xavi is a coach who played for years in Barcelona himself and that's why it's pretty much easy for him to understand the players which makes it easy to get connected with the younger players.
He usually tries to hire young players who can play for Barcelona in years because he knows in Barcelona they have older players like Lewandoski who can't play for his team in the next years because of his age.
Indeed. Xavi played for many years in Barcelona when he was a professional footballer. He is a legend, he knows well the nature of Barcelona game. So, it is not very surprising if Xavi knows well how to build Barcelona squad with potential young players. He ever experienced the time when Barcelona squad has many young players that can strengthen the club for many years. If Xavi builds the squad with old players, it won't last a long time.
Several Madrid players who have now extended their contracts such as Eder Militao (2028), Valverde (2028), Camavinga (2028), Rodrygo (2028) and Vinicius (2027) will make them pillars of Madrid for a long time. With the release of high prices, it indicates that Madrid does not want to lose these players easily.
Real Madrid has done the right decision to extend their contracts for a long time. Those players are very important for Real Madrid, they are the next generation of Real Madrid squad. I don't think Real Madrid have the intention to sell those players, they are expected to stay in Real Madrid for many years. Unless they drop their performance very much, Real Madrid will always keep them on the squad.