Fab has stayed relevant by staying one step behind Jay-Z at all times... and by having a good grasp on the "cool" of any era. The delivery and the formula has stayed the same. The references (sports, clothes, celebrities) just update with the times.
I said this in the Soul Tape 2 thread, "Fab is the most consistent AVERAGE rapper of all-time." He never releases anything truly "great" nor does he releases anything "bad". He simply adapts with the times and keeps it moving. It's a marvel how he's managed to stay relevant.
I think he gets to much props.