The difference between the Yankees and Phillies of recent years is that the Yankees keep mixing in younger players to complement their older stars. They also had Robinson Cano and Brett Gardner emerge as fine players from this strategy.
The Phillies also brought along their young players at an older age, think Ryan Howard and Chase Utley. That’s great if the team is trying to capture their prime, then let them go, but Philadelphia is keeping them around. If the oldsters all decline at once, things will get ugly.
(The above is mostly about the offense. With the pitchers, I think the Phillies assembled a great mix of new and not too old.)