Drawing a template from how these all developed and how their teachings influenced the lives of their students and their peoples it is easy to make comparisons to magic. It changed the way people looked at the world and others. This change of perception, opened up a whole new reality. The physical world and the mysteries of the other opened up immensely after these great thinkers.
I'm a big advocate of critical thinking and see it the equivalent of magic in the modern world. The difference of what can be done and the problems you can overcome with critical thought can change things as drastically as how we imagine magic should be. I see it so powerful as to not only create financial success but bring great happiness.
Although, the advancement of thought does come with some dangerous consequences:
If one learns but does not think, one will be bewildered. If one thinks but does not learn from others, one will be imperilled. - Confucius
I'm aware that selling these ideas to players is practically impossible. Going esoteric can be such a turn off. The image I get is a bunch of ideas and philosophies that really take you out of the game, into philosophical discussion. I'm not promoting that, I'm trying to do is see how pragmatically these ideas and philosophies applied.
Stories of Confucius and Budda are pretty fun as something that people encounter in their game and experiences. The anecdotes and situations they solve quite handily could have been actually very messy affairs in reality and only in hindsight they came up with their amazing answers.
Anecdotes of Confucius on the other hand, were it wasn't some amazing answers that got people to praising him BUT hard and difficult truths that kept him a out of a job until he died. Imagine the situations of Confucius in a game: where the players are up against a rock and a hard place. if he tells the truth, he can get into trouble, if he sucks up nothing gets done.
A useful story about Gautama Budda is his life and how he grew up. I like how he really was well to do and it was concern about suffering and harsh reality that lead him to make some amazing conclusions about life. I find the same basic essence of that story useful for characters. In the Budda inspiration, it is the setting dressing that makes characters look at the world where every thing is going their way, but actually it is not. That there is something very real that is being hidden from him.
Basically, stories of the great minds of the Axial Age and how they changed the world with ideas (which is a small but important part) is a great direction to take in a game. The problems they solved and the people they helped make the characters some bright innovators and bringers of change. Of course, with such ideas and the status quo there is going to be some violence and intrigue which players always enjoy, at least the causes are more meaty than just wealth.
I forgot where I heard this: "Adventures are a just bunch of homeless people stabbing other people and taking their stuff."