Maldini played untill 40 cause when his pace went away, he still had his vast array of other skills.
Alves lost his pace ? Do we remember him for pace ? I remember him for his combination ability, his playmaking from the wing, his amazing crosses and when in form his decisionmaking on the edge of the box. Decisionmaking improves with age.
I can absolutely see alves play for quite a while. When was the last time he got an injury not related to impact trauma ? Fine, he has a 4 month fracture now. Nothing to do with age, just bad luck.
Chiellini and Barzagli, collect several non trauma injuries the past seasons. Alves likely outlasts them.