i am not Man City supporters, if you think those players are best players for Barca(best of world) that is ok we don't need to make so much transfer
today we won the game but first 45 mins we can go to the half time with 2-0
our midfield and defence is really bad
today pique was good but he is getting older
we have to make renew the team
You see, the problem with these world class legendary players who are getting older is that they just don't wanna stop playing good football until it becomes physically impossible for them to do it, and that's not happening until you're 35 or so. You see the likes of Alves playing as a starter for PSG, Iniesta bossing Madrid on their home ground, Modric running things for Madrid and so on.
Alves for example would be a better Barca RB at 36 with early signs of arthritis in his joints, than Bellerin at the peakest peak of his body. There are things that count a lot at the highest level, personality, brains, character, professionalism etc. The greats rank 10/10 at most of these, so that's why they're still running the show even if they're well over 30. They may not be the flat out best in the world in their positions anymore, and they may be more up-and-down in terms of form, but they're still there, capable of showing up and winning titles, influencing games and being source of inspiration for new players.
So, instead of bringing in dudes of younger ages to replace Pique and Busi, we'll probably do it to be their 'students', and learn the ins and outs of being a world class defender or midfielder from them.
That means either talented players up to 24, or world class players aged 26-28. And those aren't free. Ozil, Sanchez, Herrera. Not good enough and/or not young enough.