Wishful thinking. Age means a decline in movement and consistency. "Out with the old, in with the new" can only be delayed for so long.
Also, somewhat related, since you lose consistency with age, you need match play to keep it. Choosing to miss tournaments can be a risky strategy. You don't want to play too much to preserve your (older) body, but you can't play too little that your game suffers. You can do it if the gap between you and the other players is wide, but when young players are biting at your heels, it's a tougher proposition. Djokovic chose to miss tournament before the USO, and maybe that explains (at least partly) his struggles early in matches throughout the tournament. Losing the 1st set in BO5 against lesser opponents is not that big a deal, but when you get to the semis/finals, well, it can bite you in the arse.