Is there evidence though that older players run out of gas in the postseason? There is clearly a bias towards playing them in the postseason over younger players, but that may just be managerial error playing older players over more talented younger players.
We just lost a few games we should have won in Arizona last year. It could have happened for a dozen different reasons. The older age of the core does make it more important to try to compete each year we have a chance. I just think we see as many instances of older rosters overachieving in the playoffs relative to talent as younger rosters (compared to their regular season record).