As a metaphor, snakes are wise and were apparently recognized as such by the Hebrews who used one of the meanings of wise as being successful. If there was no literal connection then the metaphor would have fallen on deaf ears. The metaphor only works in this case if the literal is somehow true to the listener. Or do you think the Hebrew people were being taught by Jesus that snakes had some mystical power of wisdom ?
I think that people then and now believe certain animals have mystical powers. We "modern" people would not admit this out loud, but there are innate reactions to the appearance and behavior of various animals that have made Disney rich. I bet I could find people living right now who believe snakes have mystical wisdom in the usual sense of the word.
But based on your equation of successful=wise, all living things are wise and the meaning is diluted to nothing. There is no such thing as a type of living organism that is not successful.