Also, the new players should compete with their senior in the same position there. If their senior showed better performance, a new player will be at the bench for a longer time.
New and young players need to have senior and outstanding players to help them growing up. Messi was grown up with help from Ronaldinho and in the last season you can see the help of Messi for Pedri and Ansu Fati. There are very little young players can grow up well without help from senior players. If they are put under pressure and expectation of clubs, fans, their career might be destroyed.
It seems regeneration is the problem. Because every new player seems to need a process to be as good as a senior. But the target of victory seemed to get rid of a regeneration. But it all depends on the coach in deciding everything. I hope Anceloti can solve this problem. Sometimes the club just wants an achievement without seeing a process.
In big clubs, pressure is bigger and young players have more prob to fail than to succeed. Ancelotti does not a coach who can grow up young players as I know. He works well with many types of players but does belong to list of perfect coaches for young players.