Thing is your point is very general & not going into any detail. I'll go into those for you:
What happened with Scholes & what change in his early 30s that helped him proved everybody wrong? SAF finally accepted that outscoring opposition is not always work. Improving defense is the key & starting with midfield. Mourinho talked about Makelele role that English team neglected: sealing the defense, provide an extra option to release pressure from the back. Scholes as B2B need to offer both ends of the pitch. He's not that physically gifted. Not great at timing his tackle... SAF decided Scholes should be more focus on controlling the game, being more a specialist to get the best out of his best attributes. It worked.
As I said nobody can predict future. Matic's style is different than Carrick, yes, but the whole idea is all down to the player who offer what the team need. Different teams require different need. One can say Matic wouldn't do well in his 30s, but how so? Last season Chelsea best form (defensive stability) lies with Matic in good form. When Conte decided to mix thing up, then Chelsea defensive's stability also suffered & that's when Kante was in good form. He's not better than Kante, but his role is vital.
Perisic as pointed out offer a "different" quality that we lack. If we're to go into detail about different categories of wide attacker, Perisic would be pretty high up the ranking in out out winger class in today climate. We lack goals so we just adding more goal scorers right? Why Argentina NT of this generation with that many quality proven goal scorers, often being a team who depend on their defense instead & only beat the opposition with small margin? Building the team is not just about adding playing. It takes players compatibility, chemistry into the equation too. Balance is the key word. As I pointed out few page back &
@el3mel pretty much replay the whole thing: Perisic offers proper winger work. He will not solely solve our problem, but he's an answer to one of our problem without making 2 or 3 signings/ change the system to fix this problem.
Thing is player can have a say where he wants to go. We can throw money at Dortmund, but the player doesn't want to come, it doesn't matter. Bunches of clubs, us included in for Dembele last summer & he decided to go to Dortmund. People are gullible if they believe all thing what the papers wrote. Pep was not even in Manchester & suddenly he had dinner with Dembele. Countless of Barcelona, Madrid & City linked with Pogba couple years ago. In the end we I am not saying there is not smoke in this Dembele's rumor, but there is also a huge possibility journalists are making stuff up after Tuchel's departure.