In his age 27 season, Moss had 6 ML ABs with the Phillies after having around 900 ML ABs in the previous four years. In his next 3 seasons, he had OPS of .954, .859, and .772 with Oakland and had over 1200 at bats with 76 home runs in those three seasons with the A's.
Moss is the example of someone who did come on strong after age 27. It can and does happen.
After 2014, Moss has fallen off and while it might be argued that he was better than what the Phillies might have in the outfield, frankly, he is not what they need. The Phillies need to find the player who is going to break out in 2017, not the one who had his break through in 2012. I certainly realize that finding that player is not easy, but they need to be looking.