The greatest idol was none other than physical prowess. The posukim are replete with references to this ideology. Here the posuk informs us that great name depended on physical strength. It is precisely because the world was geared to the physical that no value was attributed to old age, i.e., when the physical body is at its all time low. Along came Avraham who introduced the world to spirituality.
Spirituality is an ongoing process that gets better with time.
Thus, as a byproduct of spirituality, old age received value. Let us now review the Gemarah . Until the time of Avraham, there was no old age. This means that, until Avraham's time, old age had no value, but when Avraham introduced spirituality to the world, old age acquired its well-deserved and long awaited value. Rashi provides us with the simple explanation.