Which came first, the ism or the wisdom?
The answer is clear: there were wise people for at least tens of thousands of years before philosophical isms were invented around the sixth century BCE by the likes of Thales, Confucius, and Siddhartha Gautama. As Pierre Hadot rediscovered through his historical research into philosophy as a way of life, in ancient Greece theoretical philosophy grew out of and was secondary to the “spiritual exercises” of practical philosophy. Thus, for instance, a wise person might act stoically but that doesn’t mean Stoicism makes you a wise person. The same is true for the signature virtues of Epicureanism, Christianity, Taoism, Buddhism, and all the rest.
One thing that an ism gives you is a credo: an easy way to separate those in your group from those outside your group. Thus, for instance, in Christianity the Nicene Creed became a convenient way to determine if you were dealing with a heretic (say, a gnostic) rather than an orthodox believer. And, as far as I’ve been able to determine, the gnostics were more focused on gaining wisdom than on gaining adherents (see The Gnostic Gospels by Elaine Pagels).
The worry one hears from adherents of a particular ism is that if you borrow insights from other schools of thought then you’re stooping to mere eclecticism (which isn’t an ism in the same sense as Stoicism or Buddhism or whatever). I used to share that worry too, but then I realized what really matters is to be a successful human being, not a dedicated follower of an existing creed.