Because if, for example, Barcelona sells several of its players next season, in my opinion that is also too risky. Because, the risk is that Barcelona will not necessarily get better players than the current players. So in my opinion, utilizing existing players is a way out of the problems Barcelona is currently experiencing.
There are several players whose performance may decline due to age and I think those who are old enough can be sold and bought new players, at least young players who have more ability and have the potential to be able to play in the main squad at Barcelona, after all the competition is very tight in Next season, if we continue to play experienced players, it won't be enough because stamina and performance are necessary, especially since league matches are also quite time-consuming, having young players will be good enough to maintain consistency.
But I don't know whether Barcelona has enough money to buy new players and sell their players, even though we know they are in a financial crisis, I am not a Barcelona supporter but what I see is that Barcelona should have lots of young players to fill the main squad so they can compete in the season. in the future and Xavi can rotate each of his players so that he can continue to maintain consistency next season, at least winning the Laliga title is already a good achievement, let alone the UCL which is certainly not an easy competition to overcome.
Actually, and I also think this is the best solution for Barcelona, they should just sell their players who they know are not doing well for them again, are old enough, and can participate with their full strength in the full season. You have a point. It always takes time when the league starts, and players who are not in good shape or are old may seriously deform. If there is no other player to replace, then there will be a problem, so to me, the best thing is to get new players with good performances. Sometimes experience does not only matter; strength also needs to be involved in football.