People often believe (or are made to believe) that those who lived many centuries before could possess some superior knowledge or wisdom, and that their spiritual achievements have been lost or forgotten with time.
Such a belief denies development at least twice. First, cultural achievements are deemed to be eternal and never change. Second, people's ability of thought and action is assumed to be the same throughout the human history.
The both statements are wrong.
Nothing in the culture comes once and for ever. The material and spiritual culture are equally changeable. The commodities of the early ages will never satisfy the modern demands. But also, the esthetics of one epoch is different from another, and most samples of the ancient or primitive art will hardly excite anything but historical interest in a contemporary person. Similarly, the notions of the early science can hardly be acceptable today. The same holds for philosophy, for wisdom. Moreover, since philosophy is essentially related to practice, to the conscious construction of the future, following prehistoric directions is exactly the opposite to wisdom, which is bound to eventually break any rules at all to discover new ways, more appropriate for each particular stage of development.
Of course, some heritage of the past preserves its value in our days as well. This means that the culture has not yet surpassed the economic and social organization of yesterday, so that people still live and operate in the similar conditions. That is, the acceptability of the old forms is mainly due to the low rate of development rather than to some extraordinarily wise establishments of our predecessors; in other words, due to the lack rather than the excess of wisdom.
Now, people's abilities develop following economical development, which extends the collection of skills possessed by an average person, including mental skills. The wider view of the world makes the average level of spirituality much higher in a contemporary person than in most people of the past. Therefore, any modern wisdom will in any case be more sublime and elaborate than anything previously known. If a modern philosopher gets fascinated by some ancient "truth", one could suspect his spiritual underdevelopment rather than the exceptional quality the old idea. In particular, the persistence, despite of all the progress of the arts, science and philosophy, of numerous religions is the result of slow cultural development and poor education, which, in its turn, is due to the improper economic and social organization.